TreePeople’s W. M. Keck Foundation Nursery Native Plant Nursery is an accredited phytosanitary (clean-grow) facility. We take careful measures called best management practices (BMPs) to prevent the spread of Phytophthora pathogens, diseases, and other destructive pests that can thrive in a nursery environment. As part of these practices, we pasteurize our soil and plants are stored off the ground.

TreePeople grows and plants in partnership with California Botanic Garden, the US Forest Service, NFF, NFWF, MRCA, Seed LA, Cal Fire, State Parks, and many other partners for fire mitigation and habitat restoration projects. We supply thousands of native plants per year to communities in the local mountains and urban forestry. Our work is supported by TreePeople staff, partners, and dedicated volunteers.

About Phytophthora

Phytophthora (pronounced Fie-TOF-thora) means “plant destroyer.” They are microscopic pathogens that travel through water from contaminated material to desirable plant hosts such as oak trees, manzanitas, sages, and many others. They taste electromagnetic and chemical signals from plants and swim toward the species they need to reproduce. It causes root rot, wilting, and foliar dieoff. Visible symptoms often don’t develop until right before the plant dies. Our Mediterranean climate with dry summers and BMPs help keep them in check.

There are native and introduced Phytophthora species. Sudden oak death (Phytophthora ramorum) is a serious problem in Northern California and Oregon where it thrives in damp environments. Back in 1845, Phytophthora infestans was introduced to Ireland causing the disastrous Irish Potato Famine. Here in LA we’re keeping an eye out for Phytophthora cinnamomi aka “ink disease.” Nurseries have ideal breeding conditions with lots of host plants and water.

There is no known cure, fungicide, or algaecide to treat Phytophthora–only containment and mitigation. They can go dormant but are sensitive to high temperatures which is why we steam treat (140-180˚ F) all the soil that passes through the nursery. We spray the soles of our clean shoes with 70% isopropyl alcohol before entering, keep plants on porous tables off the ground to prevent pooling water, and quarantine plants that may be exhibiting symptoms. In the nursery, the rule is the floor is lava so try not to drop anything!

About Process

California native plant seeds have many strategies and adaptations to wait for the right conditions to grow. Figuring those conditions out is like finding a key to unlock an ancient puzzle that gives life to a beautiful plant friend–a mathematical recipe for plants. Some seeds (like manzanitas) will wait long periods of time for the right conditions to germinate. Others (like oaks) want to start growing as soon as they land on the ground or are buried by a scrub jay.

Cold stratification helps us in many ways. Some species won’t sprout without a winter sleep. It helps slow other species down so we can keep up with the number of things going off at once. For example, oaks are very quick to sprout, and cold stratification buys us time.

Many California-native species are fire adapted but not dependent (grasses, buckwheat, poppies, etc.); others are fire dependent (chamise, chaparral mallow, etc.); some just like the char and don’t need the heat itself; others need both.


We offer annual saplings for adoptions to our donors!

Check out the native plant garden kits. We do contract grows for mountain forestry and other projects. Please email nursery manager Jack Smith for inquiries.

Yes, please email Nursery volunteering opportunities take place from 9am - 12pm on Tuesdays, Wednesdays, Thursdays, and some Saturdays. Volunteering in the nursery is by appointment only.

Typically, no but we do sometimes accept seeds and acorns.  We mostly house plants from other clean-grow facilities that we contract with.