Pacific wax myrtle, Myrica californica, is a beautiful well-behaved evergreen shrub that grows fast and prefers foggy climates.

I have had bad experiences with neighbors' Rhamnus alaternus (reseeds everywhere, so is a persistent weed problem).

The first one I thought of was Tibouchina urvilleana (princess flower), one of my mom's favorites. Unfortunately, she lives in the Redding area, so hers will never be as lovely as the ones in the coastal areas. :)

Brenda

I thought about Myrica californica too but Urban Forest Ecosystems Institute says it causes allergy. Did you have any issues with allergy? I read about reseeding problems of Rhamnus alaternus and tried to ignore... but this is something we should take into consideration. Thank you!

We do love Tibouchina urvilleana (princess flower) as well. In fact, we have decided to plant near our down stairs window. We cannot wait to get this! You are right that Princess flower does not seem to be bothered by fog and overcast. Thank you :)

I have both Dodonaea viscosa ÂPurpurea and Pittosporum tenuifolium. P. tenuifolium gets much larger than 15' -- it's really a tree 30-40' tall. The Dodonaea has been good, but I wish it was denser--we have it extending the height of our fence to screen out the neighbor's roof, and it's good, but not as dense as I could wish. I think it would also like more sun than 3-4 hours.

Have you considered Prunus caroliniana. It's about the same size as the Dodonaea after a few years, and is a denser screen. Also very low water requirements once established. Mine are nice and dense and about 15' tall after 4 years from their initial 5 gallon pots. There's also a Prunus native to Catalina Island that is similar to Prunus caroliniana, but that one can get bigger than P. caroliniana. Pretty Camellia-like foliage.

I haven't noticed any allergy probs with Myrica. The male plant is rated a 9 on Tom Ogren's 10-point scale and the female a 2, which is a lower rating than any of your other plants -- Rhamnus 9, Dodonaea 8, Prunus car. 7, Pittosporum 5, Viburnum 5, Tibouchina 2.

Practically speaking, if you plant more than one Myrica and at least one is a female, the pollen should not be a problem, because it will have a place to go rather than floating aimlessly on the wind.

At the risk of confusing the issue, may I offer these other options:

Callistemon phoeniceus LESSER BOTTLEBRUSH
Escallonia x exoniensis ÂBalfouriÂ, E. laevis, E. rubra ESCALLONIA
Melaleuca armillaris BRACELET MYRTLE
Melaleuca ericifolia HEATH MELALEUCA
Metrosideros collinus ÂSpringfire NEW ZEALAND CHRISTMAS TREE
Pittosporum crassifolium KARO

Check your SWGB for details. Althoug some may be described as getting bigger than you want, they're all amenable to heavy-duty pruning to keep them in bounds.

Joe

You might check into a few of the Ceanothus varieties. Many of them grow naturally in the coastal areas, so should do quite well and are stunning in bloom.
C. thrysifolia and Ray Hartman are 2 of the taller varieties that would suit your purpose.

Here's a few links

http://www.suncrestnurseries.com/calnatives/ceanothus.html

http://www.laspilitas.com/plants/plant_lists/California_native_plant_C.htm

Catalina Ironwood is another attractive native tree
http://www.suncrestnurseries.com/calnatives/lyonothamnus.html

I like Dodonea too. I have 2. One trained as a tree and the other is a bush that provides a screen. Mine is fairly dense (maybe it's older?). Some folks on this forum had problems with it reseeding, but so far, it has not been a problem for me in the 8 years I've had the plants.

wanda

Wow! What a pleasant surprise to receive this much inspiring response. All of you know your shrubs! Thank you for your time responding my posting. I did further research based on your input and my comments will follow. I do not know the max word per posting or if any. So to be on safe side, I created one posting per respondent though I am not sure this is recommended. If any of you know this is not recommended, please do let me know for I could not find this info in forumÂs instruction page. I am still new to posting in forum.

I checked Tom OgrenÂs allergyfree_gardening.com and I am so excited to know this type of reference is available!!! Both my fiancée and I have allergy problem and his is worse. He is quarantined in a house all day long especially nice days during pollen season (like yesterday and today) that drives him crazy for he loves being outside. I have ordered "Allergy-Free Gardening" and "Safe Sex in the Garden and Other Propositions for an Allergy-Free World." We will reference these books first before we decide on our plants. This would not stop us from getting allergy but it will prevent from making it worse. I have put Myrica californica (female) back to my possible candidate list. Thank you for time looking up the rating of suggested plants and good suggestion of getting a female tree of the same kind. :)

Thank you for your great suggestions.

-Callistemon phoeniceus LESSER BOTTLEBRUSH

I could not find this in SWGB or in web search. Do you know how tall this plant will get?

-Escallonia x exoniensis ÂBalfouriÂ, E. laevis, E. rubra ESCALLONIA

We excluded Escallonia for making the following assumptions:
1. Ecallonia does not seem to grow taller than 8-10 feet even with water and care.
2. Ecallonia does not seem to be trained as a tree.
We would love to hear from you if our assumptions are wrong. We draw these assumptions looking around our neighborÂs front yards.

-Melaleuca armillaris BRACELET MYRTLE
-Melaleuca ericifolia HEATH MELALEUCA

I have probably seen these plants somewhere but do not remember if they are dense enough for our purpose. I will try finding them in our neighborhood and do more research.

-Metrosideros collinus ÂSpringfire NEW ZEALAND CHRISTMAS TREE

I always liked this tree but never knew the name. The street I take every day to work is dressed with this tree on both sides and they are quite tall, probably 20-30 feet (may be M. excelsus?). I see younger trees among mature trees and it seems slow growing. Do you know M. collinus ÂSpringfire is fast growing?

-Pittosporum crassifolium KARO

I see this planted practically everywhere I go. (Maybe because I live near ocean and work near SF bay?) SF Botanical Garden uses it to screen chain link fences and it does the job so well. I really love the slivery blue green foliage of this plant that goes beautifully with the deep maroon color of its flower. Urban Forest Ecosystems Institute marked all PittosporumÂs health hazard as allergy, except for P. tenuifolium that was marked as unknown. I had no way of telling likelihood of causing allergy but did not want to take any risk so dropped all Pisttosporum from my list except for P. tenuifolium. But now I have a further reference on this so I will definitely reconsider P. crassifolium. Thank you again.

PS: I did not know SWGB is abbreviation of Sunset Western Garden Book. So I googled it and then I got "Short for Star Wars Galactic Battlegrounds" LOL :)

sng:

I like the way you research.

Do a copy and paste for -- Callistemon phoeniceus -- and you will find considerable info on the web via Google. I have a feeling you've misspelled it somehow.

It's a shrub to about ten to fifteen feet, easily trained into a "standard" or multi-trunked "tree".

"Escallonia x exoniensis ÂBalfouriÂ, E. laevis, E. rubra ESCALLONIA We excluded Escallonia for making the following assumptions:"

Your assumptions are inaccurate. The common Escallonias are almost always trimmed into tight hedgelike masses; hence making it hard to see the potential as a small tree. Along the coast, especially, the listed ones (not so common) make great multi-trunk small trees.

-Melaleuca armillaris BRACELET MYRTLE
-Melaleuca ericifolia HEATH MELALEUCA

"I have probably seen these plants somewhere but do not remember if they are dense enough for our purpose. I will try finding them in our neighborhood and do more research."

Although these species have fine-textured foliage, they do grow into densely-foliaged small trees. I'm attaching a photo of one (they look alike).

-Metrosideros collinus ÂSpringfire NEW ZEALAND CHRISTMAS TREE

"I always liked this tree but never knew the name. The street I take every day to work is dressed with this tree on both sides and they are quite tall, probably 20-30 feet (may be M. excelsus?)."

The "trees" you see are M. excelsus and they get bigger than 30 feet. M. collinus is smaller. And conseuqently slower growing.

-Pittosporum crassifolium KARO

"I see this planted practically everywhere I go. (Maybe because I live near ocean and work near SF bay?) SF Botanical Garden uses it to screen chain link fences and it does the job so well. I really love the slivery blue green foliage of this plant that goes beautifully with the deep maroon color of its flower. Urban Forest Ecosystems Institute marked all PittosporumÂs health hazard as allergy, except for P. tenuifolium that was marked as unknown. I had no way of telling likelihood of causing allergy but did not want to take any risk so dropped all Pittosporum from my list except for P. tenuifolium. But now I have a further reference on this so I will definitely reconsider P. crassifolium. Thank you again."

There are over 160 species of Pittosporum. I doubt that all of them are allergenic. The two most common ones (P. undulatum and P. tobira) are highly fragrant and, because of that, highly allergenic to many people. P. crassifolium is not significantly fragrant (as with P. ten.).

Joe

Here is a link that might be useful: Melaleuca ericifolia

I see the Ceanothus varieties in our neighborhood a lot but did not know there are taller varieties. I am amazed so many varieties are available. C. Ray Hartman sounds perfect for our purpose. Do you know if C. thrysifolia can be trained as tree? The links you provided gave me crucial caring information that probably difficult to find elsewhere: no drip, no summer water and no soil amending. With following these three rules, the plant can live 30 plus years! And as one of the links mentions the myth of the plantÂs short life is going around. SWGB even states "As a group, plants donÂt live very long; 5 to 10 years typical." It is unfortunate if a novice gardener like me do not plant it because of this myth.

As for Catalina Ironwood, it is a good looking tree as SWGB says "handsome in grove." Do you have an experience with this plant? If so, do you know how fast this grow?
Thank you again for your wonderful feedback. :)

I have no personal experience with the tree other than viewing some lovely specimens.

Here's a link that may help.

Here is a link that might be useful: Catalina Ironwood

Catalina Ironwood is one of my favorite trees.

(By the way, it's actually "Santa Cruz Ironwood"; the subspecies that is grown in gardens is not found on Catalina Island).

It is VERY fast. With water, I had a small grove of trees put on more than six feet per year in their first two years!

They have beautiful bark, beautiful foliage, beautiful flowers.

Two drawbacks:

1. They are all grown from seed so the trees are HIGHLY variable. Some grow densely upright, some are lanky and some are compact and slightly spreading.

2. The old flowers hang on for a whole year. And they're huge brown clusters.

As for Ceanothus, there is some truth to "as a group, they don't live long". That's because (1) "as a group", it contains some fast and furious hybrids that are shooting stars and (2) most gardeners have a tendency to overwater them and/or put them in the wrong soil (some Ceanothus love heavy soil, some love sandy soil).

The best of the treelike ones are:

Ceanothus arboreus
Ceanothus megacarpus
Ceanothus tomentosus olivaceous 'Cielo'

Joe

For info and photos of many of these trees and how they'll do in various parts of San Francisco, check out the Friends of the Urban Forest site.

Here is a link that might be useful: Friends of the Urban Forest--Gallery of Urban Trees

Thank you so much for your feedback. I really appreciate your time.

I have received a Tom Ogren's "Allergy Free Gardening" book. We have looked up all suggestions you have given us and learned that everything but Escallonia (3) and Ironwood (4) is potential for causing allergy. (Habitat Gardener, it is so unfortunate that Myrica's female is hard to find. Sigh...)

We determined that we need 4 dense screen plants with 13-15'tall and 2-4 plants with at least 8'tall. So we will most likely plant at least one Escallonia (Thanks Joe for your info!) We have started whole new research from allergy free point of view and I will probably make a separate posting with new plant list once my research completes.

Last Saturday, we went out for dinner around 15th and Clement in San Francisco and we saw an Ironwood tree on a street! As Joe and Wanda recommend, it is a beautiful tree and I can imagine how super it will look in group. But two concerns: 1. it might grow too tall. 2. dead flower clusters remain with the tree all year. Since our yard is small, we can definitely see brown clusters so most likely we will have to hack them. We need to put more thoughts to this potential maintenance effort.

Coastal Camper, thank you for the link. I was so excited to learn such a link exists.

Again, thank you all for your help and I am sure I will see you all in a forum. I will let you know what we decide on.