I am sure there is an effective maximum. No cottonwood I plant will get to 300 foot.

But I think of the dwarfs as in however many inches a year. If it grows 6 inches a year in 60 years that is about 30 foot. Maybe it will start to level or go sideways but you'll have to see how long any particular cultivar had been around to get a perfect answer.

The above is a pretty good answer :-) 'Dwarf' is determined by rate of growth not by ultimate size - if the plant lives long enough, it could grow to an appreciable size. The 10 year size most plant tags and sources list is just a popular guideline for an estimation of size based on typical homeownership. Since many of these trees - even as dwarfs - take 25-30 years or more to reach maturity, the 10 year size is not overly meaningful.

And if grown permanently or even long term in a container, that is also an additional dwarfing process. The root congestion of the container and the need for frequent root pruning necessary to remain in a container will slow growth even further.

Being long-lived dwarf and slow-growing conifers can get bigger than might often be generally expected when living for multiple decades. But a cottonwood won't ever last long enough to get beyond a certain height. However it is being claimed that certain clonal aspen groves are 80,000 years old! So Populus are not always short-lived.

Ok just wondering because I was thinking of starting to grow some dwarf conifers(mentioned above) in containers while I am still living at my dads home now and when I get older and buy a new home(maybe in 10-15 years), I want to bring all those potted conifers with me and plant them in the ground in my future home. So if they are still small enough in 10-15 years, it would be easier for me to transport the pots to my new future home lol

Growing them in containers will likely retard their growth rate.

Shave the roots once a year with a butcher knife and replace the outer layer of potting medium with fresh material to keep them going in the same containers for years. This will also have a dwarfing effect on the tops. Otherwise a conifer that grows so many inches a year will be 15 x that many inches taller in 15 years, will need to have been moved on to proportionately larger containers during that time. For instance one that averaged 3 in. per year would then be 45 in. (3. 75 ft.) taller than when first acquired.

mini.. dwarf.. intermediate..and large.. ARE WORDS ... used to describe ANNUAL GROWTH RATES ... see link below ...

most estimates are at ten years .... and you can figure out.. roughly .. annual growth by dividing such by 10 ...

and yes.. at 20 years.. they should be twice the 10 year ESTIMATE size .... 30 years, 3 times .... etc ...

it can be very dependent on location ... etc ... things grow different in different places ...

the most important thing that goes in the pot.. is NOT THE PLANT .... its the media .... growing in pots is more of an art.. rather than a science .... i have gotten away with it short term .... i dont know if i would have.. long term ... MI winters with ground freeze/pot freeze ... is a little interesting to the novice ...

i would never try to sustain this for 10 or 15 years ....

ken

http://conifersociety.org/conifers/conifer-sizes/

While it is certainly true that root pruning containerized trees is the best way to manage them, I am often too lazy, too weak or too distracted to do it. I have two Picea pungens 'Sester Dwarf' and two Chamaecyparis pisifera 'Curly Top' in containers on my patio. I planted them in May of 2012 as #3s and they are now perhaps 1/3 taller than they were at planting. I haven't touched them, other than to groom the Curly Tops. Growth rate on the Picea is listed as 3-4" per year, meaning that it should be at least a foot taller than it was when I planted it and it's maybe 1/2 of that. The Curly Tops have grown even more slowly. I have many Japanese maples in containers and have never root pruned most of them, either. They grow much more slowly than they do when I finally put them in the ground, which inevitably happens. Another way to observe this is to examine a tree - conifer or hardwood - that you buy in a pot, and look at the internodal distances that indicate the past yearly growth. Then watch what happens when you plant it in the ground and it develops a big root system. The internodal distances (yearly growth) invariable increase, sometimes significantly. This is especially true of pines which have been candle-pruned while containerized. Sometimes the tree ends up looking like two: a dwarf with tight growth on the bottom and a species or intermediate on the top. Makes for a challenging pruning job...

as to your title question ...

yes.. they should retain their annual reduced growth rate ...

if you meant to ask.. will they stay small ... not necessarily .... since the WORD dwarf ... is its growth rate ... not its ultimate size ...

if i were to mess with pots.. long term ... i would work with mini's ...

dont forget.. the whole trick with pots.. is your water management system.. aka... the media ....

ken

Some good answers here-I would only add that the topic of when and why trees stop growth is often mischaracterized here on this board; Trees are not some kind of magical beings. The live, grow, stop growth and die, exactly like all living things. The process whereby this occurs was best characterized by tree researcher James Clark, who stated basically that once a certain point is reached, the difficulty of pumping water up to the top of a very tall tree overwhelms the plant's ab ilities to do so. It is a water thing; At some point, the energy costs of transporting water to great heights is counterweighed by the need to use energy for other purposes. The tree begins to slough off parts that are most distant from the roots. The top dies and tree goes into decline. It's not magical, it's not some kind of perpetual motion machine; No, all trees die, just like all animals do, and it happens when the energy balance does not favor maintaining life.

So do the growth rate slow down even more as they age? How big would a tree like cryptomeria black dragon be if its 70 years old?

resin once suggested... more carefully... as i interpreted .. lol ... .... that at something like 385 feet .. a redwood starting the ability to pump water that far ... it couldnt overcome gravity ... go figure on that.. i think at that point ... it was taking in water thru the needles ...

dude.. i gave you all you need to know to figure out the potential growth of any plant ... in any time frame ..... why should i pull out the calculator.. and look up the annual guesstimate of black dragon's ANNUAL growth rate ... find that.. multiply by 70 ....[or take a ten year GUESS .. and multiply it by 7].....

whats usually left out of the cliches ... often by me ... is TREE TIME ... when careful.. i say.. it will never stop growing 'in your lifetime' ....

ken

There are genetics involved as well. Plants are genetically programmed to attain a specific size range at maturity. Once mature and approximating a typical lifespan, the growth does slow significantly but never really stops completely until death. You or I may not notice appreciable growth on a very old, mature tree but it IS happening, just in very small, incremental measures.

Black Dragon hasn't been around for 70 years (introduced somewhere in the 80's or early 90's) so who knows exactly how large it might get. However at only 3-6 inches per year (probably less if grown in a container long term), it is unlikely to get huge in your lifetime. I would be surprised if it hit much more than 20-25'.

Well Ken only reason I'm asking is because, as gardengal said, I know that the growth rate slows as it matures so a typical 3-6 inch may be like a 1-2 inch after 20 years or something. And I don't know the exact numbers so I thought someone else knows.

So 25 feet huh.. not too big for a 70 year old which I like! So I'm guessing other dwarfs with similar growth rates like chamaecyparis obtusa thoweil and picea jezoensis landis and pinus thunbergii kotobuki would probably be around the same size in 70 years

Gardengal's addition of genetics into the conversation reminds me....the reason redwood....or to a lesser but still impressive extent, an eastern white pine or a Norway spruce gets so tall is duration of main growth event. So, to take things in the opposite direction, a flowering crab will never be 100 ft. tall. The genetics of the plant don't allow for the rapid type of growth required in trees that eventually will attain great height. At the same time, the crab's growth will slow once it reaches its 20 or so ft., cultivar-dependent. A coast redwood has the fast growth of youth, but is able to maintain this growth rate far, far into its lifespan. That's how we end up with these very tall trees. They maintain "youthful vigor" long into their lives, growing at rates similar to very young plants. In fact, for a while, people with hidden agendas were talking about how old-growth forests were a "waste" of resources because they aren't growing, are not storing carbon ( as if these people care about such matters) like young forest do, blah blah.....Meanwhile, actual research has shown the opposite; Old-growth forests continue to store carbon-in other words, continue to grow- and in fact store more carbon than an equivalent patch of young forest or plantation. So what I'm rambling about this time is, trees' size is ultimately determined by genetic potential and an environment which meets its needs, the genetic factor allowing for an extended period of growth. But tailoring an answer to some landscape cultivar is obscure in the extreme. Plus, we can't really allow for happenstance; Who knows what might befall a plant in the landscape somewhere? Is next year going to be dry? Who knows? Is another Sandy-like storm coming to the east coast? Beats me. We can provide generalities, but all of the stuff discussed in a forum like this is subject to randomness. It's pretty hard to pin down that tightly.

Except crabs aren't slow - a garden center sized specimen may be only 2 years since the initial budding - and the tallest coast redwoods are growing much more slowly than they perhaps used to, when they were younger. Also a shade suppressed example may have to wait centuries to get enough light to then take off. In the meantime growing at a snail's pace.

What giant coast redwoods pretty much always have done to get so big is living a very long time. With long-lived and slow-growing garden shrubs like camellias, rhododendrons and dwarf conifers the dominant shared histories between jumbo specimens will likewise be the amount of time they have been in place. If you wait 50 or 60 years that conifer or rhododendron that is said to typically grow 4 ft. tall in 10 years might be ~20 ft. tall.

Ancient redwoods aren't producing lead shoots that grow longer in increments of feet per year, as some of them may have been doing earlier in their lives. Last I knew it was still looking like the effective leveling off of their heights which I have described previously on this forum was due to inability to keep the tops continuously hydrated above a predetermined level.

Another thing that has been noticed about wild coast redwoods in later years is that they have been growing faster than in the past. This is thought to be due to increased atmospheric CO2, with an associated concern that the drying effects that are also being caused by climate change are going to catch up with these fog dependent trees later.

Increased c02 has made juniper much more common in texas than it once was (coupled with bad land management) certain plants use a certain photosynthetic pathway that enables them to take more advantage than other plants.

Dwarf doesn't mean slow growing. at least not just slow growing. it really means shorter tighter internodes. seiju elm for example is definitely a dwarf elm. but it can also grow pretty fast. even when it grows fast it keeps short internodes and dense branching. and while they do keep growing just like the plain species the ultimate shape will usually be different. if slow growing were the only criteria then all single leaf pinyons are dwarf.

Grow minis. No fear of getting too big too quickly.

Dwarfness is obtained via more than one pathway; Slow-growing plants are sometimes called dwarfs. Plants having the tight internodes as described above by Todd C. are one such pattern, but there are more than one ways to be a dwarf. Slow growth, short internodes, and a genetic potential of just minor stature are the lot of plants described as dwarfs. There are more than one pathways to this designation.

Dwarf or miniature = always small, slow growing means that only. Patagonian cypress is slow growing and gets huge, something else may be slow growing and also small growing.