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bearstate

Eucalyptus and Nothing Grows?!

bearstate
16 years ago

A recent phone conversation between myself and an old friend touched on Eucalyptus Trees and how due to something the tree exudes, nothing will grow within a certain distance from the tree.

Now I don't thing that 'nothing' is the last word here, but apparently, a lot of things won't grow and I'm very curious to know more about this as Eucalyptus are a member of the 'Myrtle' family and I have many Crepe Myrtles growing around here and I've already found from surfing the web, that Crepe Myrtles also exude oils, but thusfar have found no mention of properties of those oils that would stymie or inhibit the growth of other plants.

I was told that once you have a Eucalyptus, the ground remains toxic for quite some time and the only thing that can be done is to actually replace the soil?!!!

So questions, questions, questions ....

1) What Will grown under Eucalyptus?

2) What is the substance and what is its lifetime in the soil?

3) Do Crepe Myrtles exude this substance?

Comments (53)

  • gardenguru1950
    16 years ago
    last modified: 9 years ago

    Actually, that Wikipedia article is wrong. It is not based on any research (none cited); it is simply heresay -- bad information that has been floating around for years, including in many articles on the web that are non-scientific. These many articles simply perpetuate this unsubstantiated information.

    There are research summaries that have been published on the web. Do a google search and track down those actual research pieces -- written by folks with PhD's at the ends of their name.

    I won't comment on Crape Myrtle allelopathy. Never heard of such -- neither for or against.

    Joe

  • bearstate
    Original Author
    16 years ago
    last modified: 9 years ago

    Joe ... it doesn't take much to find white papers on the topic.

    Here are just a couple on Allelopathic Eucalyptus:

    http://edis.ifas.ufl.edu/HS186

    James J. Ferguson, professor, Bala Rathinasabapathi, associate professor, Horticultural Sciences Department, Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, 32611

    http://www.dfg.ca.gov/bdb/cwhr/pdfs/EUC.pdf

    McArthur, A.G. 1962
    Smith, G. A. 1980

    And here is a reference table for US Forest Service and University of Hawaii on Crepe Myrtle, checking it off as allelopathic:

    http://www.hear.org/pier/wra/pacific/lagerstroemia_indica_htmlwra.htm

    There's more out there, but ... this'll do to give you your authoritative refs.

    There is also an article I found out there that covers a survey of plants used in California Government ( City, County and State ) landscaping and Eucalyptus shows up as discontinued use due to allelopathic and other reasons. Oddly, Crape Myrtles are commonly used, and I assume ( making an ASS out of U & ME ) that this may be because the allelopathic nature of the Crepe Myrtle is not great or is unstudied. Else, Crepe Myrtle are so damned attractive that their allelopathic drawbacks are overlooked and they are used prolifically regardless. Who's to say?

    For my part, allelopathic properties in plants is as new as yesterday when I first read your reply to my post. And yes, I'm a bit concerned as to how to adapt to this new found knowledge and this new word in my lexicon. I suspect that there are many other allelopathic plants out there now. What they are and how they affect my landscaping, gardening and hobbying with plants is a black hole as it likely is for most folks.

    So now when I see a plant die or a seed fail to germinate, I have to ask a whole new set of questions. Was it heat? Not enough water? Poor soil? Bad seed? Birds got my seed? Gophers? Some chemical in the soil? Some allelopathic substance from ... that ...

    What an adventure?!

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    Actually, in the years which have gone by, we've lost most of them. We had one last year which turned into a beautiful tree over twelve feet tall, which we used for dried floral arrangements after the first frost (the leaves dry perfectly in place), but it didn't come back this year. We still have two small ones, even though we've had them growing for three years. The winters try to kill them, but they continue to spring from what's left. If you're willing to keep planting and not get frustrated, they will grow sometimes for several seasons. I'd give it a shot, unless it's a particularly treasured plant. We have slightly warmer winters down here than you tend to only ninety miles north. You could also try covering it with something light--which I wanted to try but never did.
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  • dicot
    16 years ago
    last modified: 9 years ago

    Pulled from the web:

    Studies conducted by Cornelius H. Muller and his graduate students during the 1970s indicate that terpene chemicals present in the resinous foliage and fallen leaves of chaparral shrubs inhibit germination of wildflower seeds, a phenomenon known as allelopathy. Fire destroys these inhibitory chemicals that have leached into the soil, and explains the abundance of wildflowers in recently burned chaparral. Salvia leucophylla, Salvia apiana, Artemisia californica, Adenostoma fasciculatum (chamise), and Trichostema lanceolatum are all considered "alleopathic" to some degree.

  • bug_girl
    16 years ago
    last modified: 9 years ago

    Did you try soil improvement with compost? When I first started I got terrible results no compost, then I started added it, and things got better, and better. I have a friend with a Eucalyptus she has the same problem, nothing grows, but she never did add compost. My theory untested, that over all soil improve will off set, but probably not completely the toxic from the Eucalyptus. It won't hurt at any rate.

  • mlevie
    16 years ago
    last modified: 9 years ago

    It's definitely not true that NOTHING will grow under Eucalyptus...near my house there's a clump of them with, sadly, scotch broom and poison oak growing underneath. On a recent hike on Montara mountain, I noticed that in the understory of a eucalyptus grove coffeeberry and california hazelnut survived, too.

    I read once that some people spread eucalyptus chips to discourage weeds, but that if they have any effect beyond just being nice-smelling mulch, it dissipates after three months. So if there is a toxin, it apparently doesn't really persist after the trees are removed.

  • bearstate
    Original Author
    16 years ago
    last modified: 9 years ago

    I had considered that the exudant was bio-degradable and that the story of having to remove and replace soil was overkill. However ...

    There's actually a forum at GW for Allelopathy.

    There's at least one post there where a person has a big old 'historical' Euc in the middle of a street median that partially covers the person's property. And their attempts to beautify their own property have met time and again with failure. The suggestion of replacing soil has become all too real for them, including putting boxes and other contrivances up.

    The thing too is that the exudates not only come from leaf fall, but from the roots of the Euc, which if near surface is a constant problem.

  • bahia
    16 years ago
    last modified: 9 years ago

    Bearstate,
    You seem to have totally disregarded that your so-called alleopathy might just be root competition for soil moisture and dense tree litter smothering young plants. I am certain that if you rake up all the larger litter that can bury the plants, but leave it as mulch around your understory plants, and provide drip emitters to new plants so that they never dry out, you can get shade tolerant plants established under Eucalyptus. But you don't sound the type to be convinced by people with actual experience...

  • bearstate
    Original Author
    16 years ago
    last modified: 9 years ago

    What you seem to be missing is that I don't have a Euc. I have only heard about nothing growing under Eucs and then discovered that they are in the Myrtle Family. I have a lot of Crepe Myrtles here and there are plant databases on the web that show them to be allelopathic. Further, I have other plants growing here abouts that I now know are allelopathic and who knows what others may be.

    I am just looking to learn something here about allelopathy and ... yes, how it applies to plants that may affect my situation here. To date, I am not aware of anything dying from my Crepe Myrtles. But I gotta tell you, I can see that when something does die or fail to germinate, there are a lot of variables, heat, not enough water, too much water, molds, viruses, too much sun, too little sun, too much fertilizer, too poor soil, spilled household chemical products, insects, ground hogs, birds and now, I learn ... other plants.

    Forgive me for trying to understand the environment in which I am attempting to sew my seeds and in which I am trying to both hobby plants and do some landscaping. I'm here to learn about the ground I sew.

    What a clown I think I'd be if I mulched my seed starters with stuff from an allelopathic plant and then sat around wondering if I just got a bad batch of seeds?!

  • bahia
    16 years ago
    last modified: 9 years ago

    Lagerstroemia indica is not in the same family as Eucalyptus, they are not Myrtacea. I have several Lagerstroemia x fauriei hybrids in my own garden, and have never noticed any problem with growing plants below them, and have many things that self sow regularly in the area below them that would have leaf mulch from the trees. You wouldn't want to start young seedlings of anything in an area where they would be inundated with lots of falling leaves, while in the garden with plants that self sow as volunteers, they seem to sort this out without any issues.

  • socal23
    16 years ago
    last modified: 9 years ago

    Bearstate,

    There are only a few instances were allelopathy is generally accepted, Eucalyptus isn't one of them. This is one of those things that "everyone knows" that if not flat out wrong, is at least overly simplistic.

    The fact is, any plant that will tolerate shade and intense root competition can be established under a Eucalyptus provided roots are kept out until the plant is established (no mean feat, Dave Fross of Native Son's Nursery says that roots from the trees that surround his property used to grow up into his potted plants before he started putting the pots on landscape fabric).

    Misinformation surrounds us and has made fools of everyone on one occasion or another. On an almost daily basis I cringe at statements made by even intelligent, well-educated people.

    For example, "everyone knows" that fire suppression efforts are responsible for the destructive fires that we have dealt with over the last several years in Southern California, after all, every time there's a fire we hear reporters and politicians saying it. The fact is that the plant community most of these fires have occurred in, chaparral, is not pine or fir forest adapted to relatively cool surface fires. Chaparral burns from crown to ground every single time whether the fire frequency is once in 5 years or once in 200 years. Naturally occurring chaparral fires are relatively uncommon: the fires down here are overwhelmingly human caused (naturally occurring fires would also tend to occur in midsummer under the influence of the southwest monsoon rather than during the Santa Ana season).

    Ryan

  • dicot
    16 years ago
    last modified: 9 years ago

    Ryan, I disagree with both the content and tone of your post. The primarly oil from most eucalyptus species - eucalyptol -is a cyclic ether and a monoterpene. The four most comomon horticultural monoterpenes - camphor, eucaliptol, limonene, and á-pinene - have been shown in peer reviewed studies to inhibit seed germination at higher concentrations and decrease the oxidative metabolism of associated mitochondria.

    While it is not true that nothing grows under eucs, neither is it misinformation that eucs have a negative chemical effect on seed germination. As a former Forest Service firefighter, I also believe you are oversimplifying the chapparal fire cycle and it is not an apt analogy to euc alleopathy.

    Its fair to disagree with the above statements on alleopathy. Its condescending to talk about how you cringe at statements made by even intelligent, well-educated people.

  • socal23
    16 years ago
    last modified: 9 years ago

    Bearstate,

    My apologies for any offense my post may have caused.

    Marc,

    Thanks for the civil tone, I appreciate it.

    Ryan

  • socal23
    16 years ago
    last modified: 9 years ago

    Sorry about the double post, I wanted to defuse the situation before someone less patient than Marc chimed in.


    "...cringe at statements made by even intelligent, well-educated people." Alas! Skewered by my own sword.

    My post was the result of numerous short periods at the computer over several hours (things are a bit crazy around here right now).

  • bearstate
    Original Author
    16 years ago
    last modified: 9 years ago

    SoCal23,

    I don't find myself offended.

    I do very much believe that allelopathy is a real problem to be considered when one is trying to germinate seeds and raise young sapling plants. Eucs are not the only source of allelopathic chemicals in the soil, but the story my freind shared with me about Eucs is how I first learned about this. Again, I do not have Eucs here. And someone pointed out above that Crepe Myrtles and Eucs are not in the same family as I was lead to believe when I heard Eucs are in the Myrtle family. Are they ... or are they not?

  • youreit
    16 years ago
    last modified: 9 years ago

    They are not, Bearstate. Crape myrtle (Lagerstroemia) is in the Lythraceae (loosetrife) family. Eucalyptus is in the Myrtaceae (myrtle) family.

    To make matters even more clear (pshaw!), the plant commonly called loosestrife is in the primrose family. :D

    Brenda

  • bearstate
    Original Author
    16 years ago
    last modified: 9 years ago

    Confusing, isn't it?

    And when all is said and done, web databases list Crepe Myrtle as having allelopathic properties all the same.

    I'm not sure how to deal with allelopathy in plants right now, except to have an awareness and play it safe around the ones I know I have growing here, especially with seedlings that I've invested time in and with other plants that I've invested purchase price in.

    It's an interesting curve ball for layman gardener and I'm sure lots of people ignore allelopathy and just muddle through happily come success or failure.

  • dicot
    16 years ago
    last modified: 9 years ago

    Bearstate, I don't think you should worry about it much at all - there must be a thousand other more likely garden problems than alleopathy. Especially if you do like most of us and start your seeds germinating in sterilized soil or soiless mixes seperately and grow them to transplanting size.

    Like Bahia says, most people don't have problems under crepe myrtles. I would argue it isn't because alleopathy doesn't exist, but because the concentration of oils is low and somewhat water soluble, so regular irrigation helps diffuse any toxicity. You really have to get a lot of litter buildup for it to be noticable, so cleaning up the leaves should be more than enough if you are concerned.

    Plants that have that strong odors usually have lots of terpenes (aromatic hydrocarbons) and these oils can have some limited effect in the soil. Remember when Reagan declared that pine trees cause pollution? That was the terpenes in the needles - needles that are used to make turpentine (hence, the name).

    If you are really interested, try a test: create a compost with large amounts of Lagerstroemia leaves then try and germinate seeds in that mix and a standard mix under the same growing conditions and see what you get. It could be interesting.

  • sumcool
    16 years ago
    last modified: 9 years ago

    Hmmm, these are very interesting posts.
    I live around the corner from Native Sons Nursery and enjoy seeing all the wonderful plantings under their eucs.

    Under the eucs in the "forest" on our property, there's a ground cover of vinca that thrives without care.
    Also, we've planted cotoneaster (no soil amendment - drip watering for the first year) under some eucs in our garden and they're doing fine. I do think, though, that the plants need to be very tough to thrive with the shade, the droppings, and the insatiable rootlets. Thank you Joe for your advice before we planted.

  • torrey12345
    16 years ago
    last modified: 9 years ago

    We live 1.5 mi east of Torrey Pines State Beach in San Diego. I want to plant a grevillea guadichaudii under established eucalyptus trees, with very sandy soil. Should I go for it? The plant is pretty pricey. The only true success we've had under the trees is with acacia redolens.

  • youreit
    16 years ago
    last modified: 9 years ago

    Below is a list of Eucalyptus understory plants from San Marcos Growers which I posted on another thread but might be somewhat helpful to you. Your Grevillea isn't on the list, however neither is your Acacia, so...take from it what you will. :)

    Brenda

  • stanofh 10a Hayward,Ca S.F. bay area
    16 years ago
    last modified: 9 years ago

    No doubt Blue gum has alleopathy tendencies..to lump all Eucalypts is beyond science. As a matter of fact Blue Gum extract is so potent it is used in the place of antibiotics to treat many fish farm pathogens. Even then I have seen photos of Blue Gums in habitat and there was plenty of undergrowth right up to the trunk.
    Interesting that I find tree ferns from the southern hemisphere thriving under African Podocarps in my yard. Podocarpus trees also are thought to be alleopathic.
    When it comes to the Eucs,better to think native-native Australians!

  • socks
    16 years ago
    last modified: 9 years ago

    My neighbors relandscaped earlier this year and put gazanias under their eucalyptus, and so far they look good. Not sure what kind of gazanias.

  • fouquieria
    16 years ago
    last modified: 9 years ago

    I just muddle through happily, come success or failure.

    Personally, I have a number of Schinus and Eucalyptus trees in my yard. The only adverse affects I've noticed on nearby plants are the leaf litter cover produced. Doesn't kill the plants or anything, I just have to clean off the litter once a year. Both Eucalyptus and Schinus seem to have their main drop in the middle of summer (July). Because I have a steep, exposed hillside, some of the litter I appreciate because it helps alleviate erosion.

    If I were to guess, based on my situation, I'd guess the biggest problem for surrounding plants would be water competition...followed by root competition. None of my surrounding plants have expressed any indications of poisoning of some sort.

    A shame these trees have such a bad reputation. I like them.

    A view into some Eucalyptus--
    {{gwi:551594}}

    A view under a pepper tree--
    {{gwi:551595}}

    Here's an interesting article on Eucalypt plantations and their affect on soil.

    -Ron-

  • hosenemesis
    16 years ago
    last modified: 9 years ago

    I have had great success with oxalis under my eucalyptus. Crabgrass seems to do quite well too.
    Renee

  • softmentor
    16 years ago
    last modified: 9 years ago

    according to the University of California Master Gardeners Program folks, almost all plants are allotropic to some degree. It doesn't take a lot of observation to see that not many Euc's have something growing under them.
    I suggest non plant objects under the tree, boulders, bird feeders, benches, and so forth.

  • jcin_los_angeles
    16 years ago
    last modified: 9 years ago

    Another problem with eucalyptus is its propensity to burn fiercely. An older tree can literally explode into flame during a fire. Unfortunately many homes in southern CA have big old eucalyptus trees growing right up against them.

  • socal23
    16 years ago
    last modified: 9 years ago

    JC,

    Eucalyptus has gotten a very bad rap on that score and it is largely undeserved, not because they aren't flammable but because they aren't any more flammable than many other ornamental trees.

    First there is the issue of which Eucalyptus you are referring to. The most prominent cautionary tale is the Oakland Firestorm of 1991 featuring the Tasmanian Blue Gum (naturally, the bogeyman sometimes used to vilify all Eucalyptus). What so many popular tellings of the story omit is the issue of fuel load. On top of the effects of severe drought, those trees had been severely damaged by the December 1990 freeze and had a tremendous volume of dead limbs in their canopies.

    I've seen the effect of fire on normal healthy Blue Gums, while they do indeed burn (right along with the Avocado trees they were planted as a windbreak for), they don't normally explode into flames the way the trees in that fire did.

    Ryan

  • mygarden_citlink_net
    13 years ago
    last modified: 9 years ago

    I have had three large eucalyptus, (located in arizona) one in the middle of a lawn, the other two on the outskirts of a lawn --surrounded by bedding plants --and cactus on one side of one of the plants --near the one planted in the lawn, is a olive tree --no ill effects to any one of the plants or lawn --except shade --had to remove them --to big and danger to a structure which was placed their after the trees were planted --

  • wcgypsy
    13 years ago
    last modified: 9 years ago

    I have eucalyptus trees that have been in place for 20-some years and I have never removed the leaf litter. Growing beneath them are cistus skanbergii, cistus creticus 'Lasithi', pennisetum setaceum 'rubrum', penstemon BOP, toyon, acacia, dietes, geranium incanum, salvia Indigo Spires, myoporum, and growing beneath the e.citriodora is tecomaria capensis. The plants beneath the tress have been in place for years and I use eucalyptus mulch.

  • surfcityhb
    13 years ago
    last modified: 9 years ago

    I've had success with a number of plants growing under the three eucalyptus nicholii I have:

    hebe
    mahonia repens
    berberis darwinii
    ivy geranium
    centranthus
    miscanthus transmorrisonensis
    Cleveland sage
    Santa Barbara daisy
    Ribes speciosum (fuchsia-flowering gooseberry)
    Salvia Belize form
    Argryranthemum "Silver lady"
    Pittosporum "silver sheen"
    Cape plumbago
    Buddleia

  • californian
    13 years ago
    last modified: 9 years ago

    I had Eucalyptus trees growing on my neighbors property on both sides of my property. Besides shading my property, the roots grew over 50 feet until they were under my garden and sucked the water out from underneath it. I tried growing a garden about ten feet away from one big clump of them but it wouldn't grow. Luckily both neighbors finally cut them down but they are growing back. A Euc can grow 20 feet in one year if it already has established roots from before it was cut down to a stump. I don't think they should allow blue gum or other large Eucs to be planted in suburban neighborhoods. There is one huge one growing about two hundred feet from my property and it blocks the sun out most of the afternoon in all seasons except summer. People don't think what a tree will look like or how big it will be twenty or thirty years later.
    A tree trimmer just offered me 25 cubic yards of shredded Eucalyptus tree trimmings for free, but I turned him down, I didn't want to take a chance of poisoning my soil.

  • wcgypsy
    13 years ago
    last modified: 9 years ago

    I wish he were close by and offered it to me, I'd grab it in an instant. We've had eucs on our property for 20-some years....very useful. We use only wood heat and we've never bought wood, the mulch from our trees is used everywhere on the property and I never have enough.

  • segurelha
    11 years ago
    last modified: 9 years ago

    In Portugal, eucalyptus is our 2nd most common tree. It is not a invasive species per se, but it is highly planted and little grows under it, and creates a kind of "green" desert.

    No animal life under it. And little plant life.

    Thankfully, oaks, chestnuts, acacias and mimosa, can all grow under the eucalyptus if they have some clearing, and therefore start to regenerate the forest again. But a heavily planted eucalyptus forest usually only lets acacia (another invasive to spread inside the eucalyptus forest).

    Other that that, heather, ivy, vinca are amongst the few to be able to grow under the eucalyptus. Blackberry is perhaps the only edible plant that sometimes grows (and rampant) into eucalyptus forests.

    I can't say that eucalyptus is allelopathic, but definitively little grows under it, and it creates a desert in biodiversity. The soil under eucalyptus is usually very dry, poor and full of their thick leaves. The soil under a native forest (mostly oak and chestnut) is much more rich in humus, with humidity and thriving with other plants. Under pine the soil is usually dry, acidic and only with some native species (but not much). Under a acacia forest, usually there is much shade, humidity but very little biodiversity (due to perhaps the strong shading and single species forest)

  • mbahenabrian
    6 years ago

    eucalyptus is allelopathic. it produces chemicals that inhibits the growth of other crops/trees.

    it also has a deep root system which makes it easy to take up all the nutrients that would be available for other crops/trees/shrubs, that is why weeding is easy and not regular in the management of eucalyptus plantations.

    the advantage of it is that it coppices after cutting it. follow that link for some othe little infomation. goodbye. mbahenabrian@gmail.

  • stanofh 10a Hayward,Ca S.F. bay area
    6 years ago

    Whoa,some names there that were huge then,never post anywhere now. One isn't even into gardening now,just maintains what he has. 10 years. Time goes one..

  • stanofh 10a Hayward,Ca S.F. bay area
    6 years ago

    As far as answer? Now that its 2017 not 2007 and old Windows XP days-lol, You should try Google maps and look at the streets in Australia. Gives you idea of what they grow under them.

    What I notice is- Australians are big on natives. Much more then Californians.

  • PRO
    uuuu
    5 years ago
    last modified: 5 years ago

    I'm an Australian and we despise gum trees, but our greenies love them!

    And our many local governments plant them everywhere they can... many have tree protection rules that stop you removing any tree... especially not a precious precious native!

    Gumtrees (eucalypts) are allelopathic. So councils put down sharp wood chips under all the gum trees they are planting, so nobody notices the death of the grass and shrubs. Of course the wood chips mean you can't sit under a tree anymore because they are dirty and sharp.

    But who said parks were for kids and ball games? Our government thinks they are for re-creating primeval forest!

  • JXBrown (Sunset 24, N San Diego County)
    5 years ago

    My husband parked under a euc once. Fortunately he wasn't in it when the branch fell (he wouldn't have been hurt, but he would have had a heart attack). The passenger side door and front and rear quarter panels did not need to be repaired or replaced ... every other body piece did — the branch pretty much wrapped itself around the car and bounced a little.

  • planetbob
    5 years ago

    Anecdotal evidence: Our landscaping department took out a dead crape myrtle next to our patio about three years ago. In the process, they mixed a lot of wood chips and sawdust into the soil - now hardly anything grows there. I've had success with a few succulents but that's about it. Part of the area is supposed to be lawn and both myself and the landscaping department have tried to grow grass there. It seems to flourish until the roots get deeper and then it all suddenly dies. There is no other explanation for it - not weather, not lack of water or nutrients.
    My next step is to replace the soil and see if that fixes the problem.

  • valeriesgarden
    5 years ago

    There is a park behind my house with eucalyptus, they are planted in a single row and have been there for decades, there is grass growing right up to the trees.

    Also nearby are two housing developments that are heavily landscaped with eucalyptus. Although some things grow, most of the area around them is barren, likely due to the fact that there is a lot of shade from them as they are planted in clusters. Even in that area there are some houses that have fabulous low shade gardens full of plants.

  • HU-929729932
    4 years ago

    I have a few tips for growing under Eucalyptus.

    I live on the edge of a native Eucalypt forest and run cattle on the family farm. We have gum trees well over 300 years old, they are beautiful habitat trees and provide more firewood than we need just from the deadwood they drop.



    If you want to grow under them the first mistake people make is digging the soil.

    Instead you should make a mound this will also help disperse the leaves and sticks that build up.

    Lay down cardboard on top of the leaf litter then add dry lawn clippings or cheap mulch and compost dry lawn clippings again until you're a foot or so off the ground add soil and plant.

    Also maintain your Eucalyptus, remove dangerous deadwood hanging from the trees.

    In Australia 95% of our rainforests and about 70% of our forests have been totally cleared.

    I feel absolutely blessed to have these trees, they provide so much habitat once they get old, they form hollows for bats, possums, sugar gliders, birds, snakes, to live in, one of the older ones even has a bee hive.

    We had a crazy bushfire last summer during the worst draught recorded in my area and a lot of old trees in the forest were burnt to the ground but at the same time I noticed a lot of trees with small hollows get burnt out and recover creating new habitat.



  • gardengal48 (PNW Z8/9)
    4 years ago

    A great many plant types exhibit some degree of allelopathy........including eucalyptus. It is a naural defense mechanism plants have developed over the ages to outcompete other types of vegetation that can threaten their seed germination and development. Often, the allelopathy is not generalized but rather quite plant-specific. Some plants are immune....others seriously affected.

    This is an area of plant morphology that has yet to be fully researched and documented but it does exist and with many, many different species and to varying degrees. It is not something any serious gardener should dismiss out of hand.

    Trees with measurable allelopathic effects. (note the extensive footnotes documenting this publication)

  • Kath
    4 years ago

    I'm reading this thread because I've just bought a house on 1/2 an acre with lots of mature eucalypts. I live on the Gold Coast, Australia, so the trees are native, and in my neighbourhood the eucalypts are important habitat for koalas, as well as for lots of birds and other animals, so I am very happy to have them. Other people must still be reading it as well, so I'm sharing 2 links that might be helpful when it comes to gardening under gums: http://anpsa.org.au/APOL34/jun04-4.html from our Australian Native Plant Society, and https://www.abc.net.au/gardening/factsheets/gardening-under-gums/9431582 from a well-known expert on Australian native plants. (Thanks to gardenguru1950 for his list much earlier in this thread. I've noted the Australian native plants that you suggest, as there are many in your list.)

  • stanofh 10a Hayward,Ca S.F. bay area
    4 years ago

    If you look at photos Kell has put on Dave's Garden website,she has posted hundreds or more of native Australian plants ..virtually every one unknown to the trade but gives you idea of why Eucalyptus forests in Australia are not all barren lands under the canopies as some might think

  • HU-645884602
    4 years ago

    Ancient thread- I know! I have grey box silver wattles mess mate and Vic ash every 2 to 3 metres on my property in Victorian central highlands Australia. Mulberriries grow comfortably. There is no soil toxin of issue. I compost eucalyptus leaves and bark for use on my raised vegetable beds without a problem for 7 years now. Competition for water and nutrients is brutal. Thank you. Great comments on this thread though- was checking to see if anyone had luck with plums apples chestnuts or almonds. Cheers.

  • perfectusinfinitusvita
    4 years ago

    Came here during some research I'm trying to do on this subject
    because of some potential plans I have on planting one of a few
    eucalyptus species, and while there's a lot of good
    information/discourse here on variables concerning affected plants,
    mulch quality, effect on soil, and other factors that may affect plants
    such as water and root competition, I'm kind of noticing a pattern here
    and elsewhere: There's a lot of lumping eucalyptus into one umbrella
    category...Guys, there's like 700 something species in this genus; they
    are not all created equal. I think that also may be partially why there
    seems to be so much debate over the subject, two different people could
    be very well talking about two different species. I'm not saying
    everyone has to be a friggin botanist over it, but it really is helpful
    to know what species any given person is talking about. Maybe then we
    can start to notice a pattern with one given variety or another. Just my
    two cents.


    As an aside, I kind of think climate may
    have a non negligible part to play. I could definitely see these
    chemicals hanging around in the soil a lot differently in a more arid
    environment with lots of organic matter build up versus a wet rainy
    tropical environment where everything either leaches away or decays as
    fast as you can blink at it.

  • Gemma
    3 years ago

    Does anyone know if I can plant ferns under a eucalyptus tree? I live in Scotland.

  • stanofh 10a Hayward,Ca S.F. bay area
    3 years ago

    Yes!..look at what grows under them in Australia. Only limited there by shade of the bigger trees.

    Plenty of Aussie ornamentals to try..like mini bottle brush for one.

  • Kath
    3 years ago

    @Gemma, I've got soft bracken fern, Calochlaena dubia, (different from ordinary bracken) growing naturally under my eucalypts, and it's a very nice looking fern. My climate is subtropical but it's a very hardy species and grows naturally in Tasmania and tolerates light frost, so it may grow in Scotland, depending on which part. See info in the links below. I've no idea if you can buy it in Scotland. Choosing a fern that grows in poor soil (because of the trees grabbing the nutrients) may be the key. There are also some epiphytic ferns and they might also be good because they don't draw their nutrients from the soil. You can plant many of the epiphytic ferns in the ground. Or just heap up a bit of soil around them to avoid distrurbing the tree roots.

    https://bie.ala.org.au/species/https://id.biodiversity.org.au/node/apni/2914179

    https://www.gardeningwithangus.com.au/calochlaena-dubia-bracken-fern/

  • Gemma
    3 years ago

    Great, thank you both for your answers,