Ask Mr. Smarty Plants

You are probably looking for a small tree or large shrub that you can trim into a tree shape. And I'm not sure if only one of them needs to be small or if you have a narrow rectangle of dirt between your walk and driveway in which you want two trees. I am predicting that you also don't want to have to baby these trees so I'm selecting trees that can grow in dry conditions. The larger the tree, the larger the root system, and the more likely it is to be stressed by all that cement or do damage to it.

I went into the Explore Plants section and selected plants for Southern California and then narrowed them down to trees/shrubs from 12 to 36 feet that grow in dry soils.   You can read about the size each plant is expected to get and also see if it is suitable for your soil.  Pick trees or shrubs that need moderate to low moisture as well.

Cercocarpus montanus var. glaber (Birch-leaf mountain-mahogany)   This is a small tree, only 8-20 feet tall. It has inconspicuous flowers so they won't fall and make a mess. And it has silvery, feathery seed heads in the fall, which sounds beautiful without being too messy. And it is a nitrogen-fixer and is drought tolerant so won't need babying. There is one on display at Santa Barbara Botanic Garden - Santa Barbara, CA.

Chilopsis linearis (Desert willow)  This tree may be too messy for you but I really love it. It blooms heavily in early summer and then after rains. You can find cultivars in shades of white, pink, and purple, some with yellow throats. It is also an open tree wih willow-like leaves and might not give you the amount of shade you want.   However, some cultivars can have much thicker foliage. I would check with a nursery or with someone that has this tree and see how messy it can get.  My trees are still very young and I don't see much mess.  They are not by a driveway either, so I don't notice. These trees need to be dry and don't want fertilizer.  They bloom better if they have to dry out between getting water.

Adenostoma sparsifolium (Redshank)  This shrub looks like a multi-trunked tree and grows 6 to18 feet. It likes sun and dry soils. The older wood has red-brown exfoliating bark which might be interesting.

Cercocarpus montanus var. minutiflorus (San diego mountain-mahogany) This is an evergreen shrub native to only your area.  It is exhibited in the Santa Barbara Botanic Garden - Santa Barbara, CA.

Juniperus californica (California juniper) The wildflower center doesn't have a picture of this but it should grow to well over twelve feet and be evergreen. It is also exhibited at the Santa Barbara Botanic Garden.  Time for a trip to there? And we would love pictures of those trees we don't have. Information on how to submit your pictures is here.

Morella californica (California wax myrtle) This is the western version of one of my favorite shrubs. It will grow as a tree if you keep it pruned up. And it is aromatic so should feel good to walk past it.  And I love the blue-green berries and the myrtle warblers they attract.

I hope one or more of these trees/shrubs will suit your needs and blend well with your other plantings. If you want to try a larger tree, you can go to the Explore Plants link, Recommended Plant List for Southern Calfornia, narrow to Trees  and then go through this list. Then see if you can find someone growing this tree or who can tell you whether it will survive your very narrow planting area and if it may damage your walkway or driveway.

Cercocarpus montanus var. glaber

Chilopsis linearis

Adenostoma sparsifolium