Native Plants

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Sunday - June 16, 2013

From: San Jose , CA
Region: California
Topic: Shrubs
Title: Tree or shrub with non-invasive roots from San Jose CA
Answered by: Barbara Medford

QUESTION:

I am looking for a small tree/ large shrub (non higher than a one story roof) with non-invasive roots to replace a 25 foot cedar. It is in a small area (5x 7) bordered to the side by a driveway, front walkway curves in front, and a concrete porch behind. It has an a full eastern exposure. Shade is not a criteria.

ANSWER:

Tree roots don't mean to be invasive, but their roots have to have a certain amount of earth and exposure to air for their roots in order for them to survive. Obviously, you are concerned with all the impervious surfaces surrounding the planned area for the tree. Please see this previous Mr. Smarty Plants question on a similar subject. Please note these comments in particular:

"You can read the recommendations from Iowa State University Extension Service for Sidewalks and Trees which bases the distance trees should be planted near pavement on the mature height of the tree. Their recommendations are:

1. trees with a mature height of less than 30 feet, 3-4 feet from pavement,
2. trees with a mature height of 30 to 50 feet, 5-6 feet from pavement,
3. trees with a mature height of greater than 50 feet, at least 8 feet from pavement."

Since your plant will be surrounded on three sides by concrete, you will have to figure the distance in feet from each of the concrete surfaces - porch, walkway and driveway. Using our very poor math skills, that sounds like you need a space at least 8 to 10 feet in diameter for even the smallest tree. We don't know exactly how high your roof is, but we are thinking you would do best with a shrub which has an expected maximum height of 12 feet.

We will go to our Native Plant Database, scroll down to Combination search and search on California, "shrub" for Habit and 6 to 12 ft. for Height. If you wish to refine this list, you can make your own selections for height, leaf retention, bloom time, etc. Follow each plant link on our list to our webpage for that plant to learn its growing conditons, light requirements, and so forth. We will check the USDA Plant Profile Map on each plant we list to make sure it grows natively in or near Santa Clara County, in Central California. This should help ensure that the soil, climate and rainfall where you live will be compatible with the shrub you select.

Shrubs for Central California:

Amelanchier alnifolia (Saskatoon serviceberry) Map

Arctostaphylos pungens (Pointleaf manzanita) Map

Cephalanthus occidentalis (Common buttonbush) Map

Ceanothus velutinus (Snowbrush) Map

Cornus sericea (Redosier dogwood) Map

Fremontodendron californicum (California flannelbush) Map

Philadelphus lewisii (Lewis' mock orange) Map

Quercus douglasii (Blue oak) Map

If you have difficulty finding the California native plants you select, go to our National Suppliers Directory, put your town and state or just your zipcode in the "Enter Search Location" box and you will get a list of native plant nurseries, seed companies and consultants in your general area. All have contact information so you can inquire in advance whether they have what you are looking for.