Overlooked Plants for the Native Garden – Native Plants Don’t Need No Stinkin’ Fertilizer!

By Lee Gordon Native Garden Committee

This is part of a short series on some of our local native plants that are superb for our native gardens, but which are largely overlooked.

One of my favorite places to walk is along the ridge leading to the Ramona Overlook in southeast Poway. This is a lesser-traveled fork of the Iron Mountain Trail, and it traverses some of the most beautiful chaparral you will ever see. It is what I wish my garden could look like. The plants here are diverse, robust, floriferous, and perfectly spaced. And nobody fertilizes them. Obviously, these plants need nutrients just like any other plant, but they get what they need from the native soil. This is the underlying point when we hear that native plants don’t need fertilizer, and it is certainly true.

We often find nice stands of native plants, while just a little bit away, the plants are sparse. Why do they grow here, and not there? We cannot see what the roots encounter underground, but uneven nutrient content could certainly be a factor. I explain that the plants in my garden are the ones that are still alive, and the same idea applies to native plants in their habitats. The plants we see are the ones that have suitable growing conditions, including suitable soil nutrition.

Our gardens are different from native habitats because we decide where the plants should grow, not nature. The plants take what they get, and at least in my experience, they don’t always get what they need. I am learning that supplemental fertilizer, in addition to supplemental water, makes a big difference.

What first got my attention was growing willowy mints for our habitat restoration project. Without fertilizer, my seedlings were insignificant, unusable, and downright pitiful! After I started watering them with half strength MiracleGro, they grew from seed to vigorous 6” plants in 2” pots in less than 2 months. Once planted, these seedlings just keep growing. Then I tried fertilizing mission manzanita seedlings. In our open spaces, mission manzanitas typically grow to a whopping 3” in 3 years. My fertilized seedlings grew to 6” in a few months. Al Field planted one in the Pt. Loma Native Garden that was 8 months old and 2’ tall!

Wooly blue curls has a reputation for being one of our most difficult plants. Everyone wants to grow them and everyone complains they cannot keep them alive. Our problem is that we have been guided by conventional wisdom that is flat wrong. One of my favorite web resources confidently proclaims that fertilizer kills woolly blue curls. Watering kills them too.

My garden has around ten woolly blue curls. Three are beautiful big plants. With monthly water, they bloom heavily in the spring, and then again, just as heavily, in the fall. Most of the rest of these plants were in various stages of decline.

Last fall, I started fertilizing them, and the results are gratifying. All of the plants, the troubled ones included, are growing better than they ever have. They are putting on lush green foliage, and woolly blue curls’ habit is that new foliage soon transforms into intense blue flower stalks.

I have seen similarly encouraging results with other plants in my garden. A heart leaf keckiella that has never done much is rapidly expanding with new foliage. Blue eyed grass surrounding one of my runt wooly blue curls produced a terrific display of blue flowers. Eight years ago, I planted a mission manzanita seedling that has grown barely 18” high, always with sparse leaves. This spring it has already added its second flush of leaves, with leaves larger and prettier than ever. Several two-year old snow drops are in bloom already.

My method consists of walking around the garden with a bucket of GroPower (5-3-1), spreading it just before a rain storm or an irrigation cycle. I throw extra handfuls under large plants (i.e. cherries and scrub oaks I want to grow into trees). I do not fertilize everything; I mark the plants I want to fertilize with flags. I figure that, in time, as plants reach the size I want, I can cut back, or even eliminate fertilizer.

Given what I have seen with my woolly blue curls, I have a theory. My first plants grew well, then died. CalFlora comments that they typically last just a few years. I’ll bet that woolly blue curls are heavy users of nitrogen, and that they deplete the soil. When the nitrogen is depleted, they die. Fertilizer solves that problem.

If you have some woolly blue curls that are on the way out, fertilize them and see what happens. What do you have to lose?

Part II of my article on perennials will appear soon.