Winter a good time to plant native shrubs in Sonoma County

Question: I would like to plant some drought-tolerant native shrubs using varieties that will grow well in Sonoma County. Can you suggest some varieties and guidance on how to plant them?

Answer: This is a good time of year to plant native shrubs! Cool weather gives plants time to establish roots in their new location before spring rains and summer heat stimulate top growth. Buying a shrub is an investment. How well that investment grows depends on the type of plant you choose, where you plant it and the care you give it.

Selecting and planting drought-tolerant natives is wise. Home gardeners play an important role in preserving insect and wildlife populations by creating pockets of habitat space in cities, towns and rural areas when planting local native shrubs.

What to shop for

You can choose native shrubs based on their flowering and/or foliage characteristics.

For example, California wild lilac (Ceanothus spp.) is a favored habitat and landscape shrub treasured for its blue to purple blossoms and its role as a magnet for bees, butterflies and other pollinating insects. It’s drought- and deer-tolerant. Sonoma County Master Gardeners consider it a Sonoma County “superstar” — a plant that’s likely to be successful in our climate. See more of these superstars at bit.ly/3XjunCz.

Sonoma County native Arctostaphylos ‘Howard McMinn’ is one of the most drought-tolerant and garden-friendly manzanitas. See other recommended shrubs that don’t require a lot of water and are native to Sonoma County at bit.ly/3ZEM8OX.

When shopping for your shrubs, first make sure the one you buy has a healthy root system that is well-distributed within the container. A balanced distribution of roots helps ensure the best anchoring for your shrub. Also, look for candidates with full, healthy-appearing foliage with minimal damage to leaves and stems.

When selecting a planting site, make sure all sides of the shrub will receive sun as it grows to maturity. Look for a location with well-draining soil. The roots of a new shrub will be starved for oxygen if you plant it in soil that does not drain well.

Test drainage and check the location before planting

To test soil drainage, dig a hole about 1 foot deep, fill it with water and let it drain, then fill it once more. If it takes more than three to four hours to drain on either filling, the soil has a drainage problem. If this happens, you have two options: find a different location with soil that drains well or plant the shrub on a slight mound.

If your planting location has a significant gopher population, consider using a gopher basket. Keep in mind that as the roots grow inside the basket, they may circle in on themselves and become root-bound, which will slow the growth of your shrub.

When you are ready to plant the shrub, dig a planting hole that is about as deep as the root ball, but two to three times wider. Be careful not to plant the shrub too deep. Create a small cone-shaped mound at the bottom of the hole and drape the roots evenly over the mound. When planted at the proper height, the shrub’s roots are below the soil level.

The best way to plant

Backfill the planting hole with native soil. Don’t add fertilizer. Firm the soil as you go to remove air pockets. Finally, create a shallow moat or basin around the shrub with an outside radius about 2 feet from the stem/trunk and water thoroughly. Fill the basin numerous times to settle the soil around the roots and remove any air pockets.

Finally, add a layer of mulch 2 to 3 inches deep around the base of your newly planted shrub, with a mulch-free zone 1 to 2 inches from the base of the stem/trunk to prevent decay. Mulch helps warm the soil, minimizes weed growth and reduces surface evaporation.

After planting, water the shrub as needed to keep the soil moist. Water more frequently during hot, windy weather until the shrub has grown several inches. Continue watering until mid-fall, tapering off as lower temperatures require less frequent watering.

Contributors to this week’s column were Tim Coyne, Patricia Rosales and Rob Williams. The UC Master Gardener Program of Sonoma County (sonomamg.ucanr.edu) provides environmentally sustainable, science-based horticultural information to Sonoma County home gardeners. Send your gardening questions to scmgpd@gmail.com. You will receive answers to your questions either in this newspaper or from our Information Desk. You can contact the Information Desk directly at 707-565-2608 or mgsonoma@ucanr.edu.