As you know, I'm taking college classes in landscape horticulture. One of my courses is in identifying and designing with California native plants. I love native plants; I would say that my current gardening obsession actually started with them many years ago. I've been to more native garden tours than I can count, read more books on the subject than I can list here, and have done extensive research and taken workshops on these plants. And yet: In just two weeks at Merritt, I've learned more than the last 10 years figuring it out on my own. One thing has become crystal clear to me, and that is that any success I've had with natives has been 90% luck. Because I've done a lot of things wrong.
Yesterday we studied manzanitas (Family: Ericaceae; Genus: Arctostaphylos). I have several of these plants in my garden, for several reasons: They have beautifully colored branches, often deep red; they have wonderful blossoms that native bees and hummingbirds really like; they produce berries, some edible by humans, all edible by birds; and they require very little water. To that end I have sited them in my garden in places that receive zero irrigation. And that is correct, I have done at least that right. But manzanitas (most often, not always) naturally occur in very lean soil, on slopes and ridges, or bluffs and coastal scrub, far away from nutritive clay. I have clay soil in my garden, which has been amended with compost and lots of other organic matter. This means my soil is very rich. Clay soil is not only dense physically (lacking oxygen when wet), it is also highly charged and nutritious; just what manzanitas do NOT like. If I had planted them correctly, I would have added a lot of sand to the soil, piled up a little berm so that water runs off, maybe topped it off with rocks or gravel, not wood mulch. Arctostaphylos gets its nutrition not from soil, but from mycorrhizae, fungus that grows in association with its roots and transfers food that it mines from the surrounding minerals. I don't remember planting my manzanitas (it was a long time ago!) but I do know my usual methods, and I assume that I planted them in extra compost to 'give them a good start.' I didn't know any better.
Despite my wrong method of planting these manzanitas, they have thrived and bloomed every year, and are large and happy. I can't explain this. All I can say is that once I planted them, I left them completely alone. No water, no fussing; an occasional very slight haircut just to keep them manageable, but nothing extreme. And that seems to be what Arctostaphylos likes with regards to maintenance - abandonment, basically. My teacher says that's actually the goal with native plantings. Total abandonment. If you can't do that, you've put the wrong plant in the wrong place.
We also studied ceanothus (Family: Rhamnaceae; Genus: Ceanothus), which I have in my garden as well, mostly for the bees but also because they are beautiful. Most of these genera also prefer lean soils; coastal sage scrub or chaparral communities. Again, they survive in my garden, likely for the same reason the manzanitas do - I plant them in dry areas and leave them alone. However I have lost a few ceanothus, and I think it's because those were in areas that received irrigation. I also pruned one of them very heavily to keep it out of a path, and eventually it bit the dust. Though it's true ceanothus are naturally shorter-lived than manzanita, because they are nitrogen-fixers; like legumes, they pull nitrogen out of the air and put it into nodules at their roots. All nitrogen-fixers live brief lives, I suppose because they are working so hard while they are alive. Many ceanothus prefer coastal conditions, but quite a few like it hotter and drier, and I guess I lucked out by choosing those varieties.
I'm sharing all this because I know many of my readers are also lovers of California native plants, and like to make space for them in home gardens (which is a noble pursuit). Here's what I recommend you do (and what I'll be doing as I plant in future): Take a lot of time to research the plants before buying them. Most nurseries give cursory information about planting at best. For native plants, there are a few good resources that will help you determine the best placement for a plant (and perhaps whether even to buy it at all). These resources are: Las Pilitas Nursery, San Marcos Growers, California Flora Nursery, Native Sons Nursery, the CalFlora website, and the Jepson Herbarium website from UC Berkeley. These websites will help you understand what the ideal planting conditions are BEFORE you plant.
A word about plant communities: I've known about them for many years, but I can't say I have planted according to them, to my garden's detriment. Let's take my yard as an example. It is flat, it is comprised of clay soil, it gets extreme temperatures (over 100 many days of the summer, below freezing many days in winter), it is extremely dry for most of the year (if not irrigated), and is surrounded by streets and concrete. It has had an inordinate amount of organic matter mixed in as well as been covered by wood chips. Some of it is shaded by very large, mature trees, and there is a lot of leaf litter. Some of it gets no shade at all. There are microclimates within its boundaries; some areas stay wetter and cooler longer, some are ovens with hot, trapped air (by the way, the ceanothus and manzanitas are located in the oven sections, that probably helps them). I have to be brutally honest about the basic conditions of my yard in order to have planting success. There is no sense in having a coastal or island plant in my garden. It will not survive.
One of my goals for this year is to revisit the areas that are regularly irrigated and decide if there are some plants in those areas that would prefer to be moved.
Lastly, I want to let you know that there will be no Weekly Walkthrough video for the next two weeks. This weekend, our computer will be in the shop, as it needs a new part. Next weekend, Kate and I will be in Sacramento at a theater competition.
Here's hoping for more planting successes in the garden this coming year, for all of us!