Mulching coastal sage scrub and chapparal plants

[Anonymous]

What is the best mulch for the plants of these communities? Las Pilitas says shredded redwood bark with rocks, other sources say inorganic only for chapparal, others say anything you can get a hold of e.g. any bark chips. Also, what is the best source for mulch in bulk for a large area? Buying bags from the nursery can be expensive. And, what about using cocoa mulch? Okay for natives?</p>

[Anonymous]

Lisa -

With regard to the cocoa bean hulls, my notes from a lecture say: Cocoa Bean Hulls - Don't ever get the lime-processed type!' However, I have no idea how well they would work with native plants.

Personally, I think gravel is the best mulch for chaparral plants, because it is most like the medium in which they grow in the wild. Bark mulches make more sense for shaded, forest plantings. That said, we must remember that gravel mining is an extractive and damaging industry, and gravel is expensive. Many native plants will tolerate bark mulches as long as the mulch is kept away from the crown of the plant.

Organic mulches can be bad for plants that need summer drought, because the mulch can retain water that fosters the growth of pathogens Bark or other organic mulches can keep the soil moist around the root zone, which is not a good thing for plants that require a dry season. Mulches can also enrich the soil, which is desirable in a forest setting or in a vegetable garden, but not in a chaparral landscape. Some plants, like manzanitas, really need a nutrient-poor soil in which pathogens cannot thrive.

I'm not sure what Bert Wilson means by bark with rock, as I've never seen them combined. He's always worth listening to, and has years of experience growing chaparral plants, so you might want to contact him and find out more. The plants that might not do well with bark mulches would be things like manzanita and flannel bush Fremontodendron that are harmed by moisture around their trunks or roots.

Hope this helps,

Lori Hubbart</p>

[Anonymous]

Thanks for your response, Lori. It occured to me that redwood bark might be too nutrient rich for chapparal and coastal scrub plants, which is why I was asking. I wasn't aware that using gravel might not be the most environmentally wise thing to use, given it's source. Someone at Theodore Payne nursery told me she mixes redwood bark and pea gravel for mulch.

I'm still left confused as to what to do, as I have many new plants in the ground and need to conserve water so I don't have to water so much until they're established and so I don't kill them by doing so. I'm going to try not to water this summer and as I live a mile from the ocean, the summers are relatively mild, so I'm hoping they survive. Do you think it would be safe to mulch with bark since I will be doing little or no watering this summer? What do you mulch with, or do you at all?</p>

[Anonymous]

Lisa,

I live in the San Diego State area. I have tried many types of mulches. I think that Lori Hubbart's comments are great. I think that using no mulch is typically the best approach for these types of plants. Wood chips retain too much moisture and promotes Bermuda grass. Rocks such as cobbles overheat and burn small seedlings. I have successfully used small branches to create a mulch-like effect and to protect small seedlings from chickens and children. The branches breakdown slowly and allow the soil to breath. This approach has been very successful with toyon, laural sumac and lemonaide berry. Good luck. </p>

[Anonymous]

Have you considered Las Pilitas' recommended practice of large rocks, rather than gravel? If you are near the coast you might be able to gently 'acquire' a sufficient number to place next to the plants, as they do at the nursery, without having to immediately cover all of your ground with mass quantities. Though this won't keep the weeds down, this will at least reduce evaporation.

Just a thought. Good luck!</p>