Why is my garden so brown?
“Why is my summer garden so brown and tired?”
I hear this all the time from clients in summer. And they’re often really distressed! So I want to talk about why your garden looks the way it does right now, what that says about the current conditions, and how to deal with what you have right now.
First, we need some background:
California climates are characterized by long, warm summers with low rainfall and lots of sun. Long dry spells are physiologically stressful and taxing on plants, who rely on water to keep themselves upright and alive.
Plants do something called “transpiration”, which, very simply, is the process by which water moves through a plant, eventually being evaporated out of the leaf through holes called “stomata”. This means that plants are constantly losing water through their foliage.
Dry foliage also burns and withers more easily in the sweltering California sun, wasting vital resources on constantly replacing vegetation which can’t photosynthesize correctly when dry.
Surviving the summer heat with aboveground vegetation requires deep, expansive root networks, which are expensive for plants, and require many, many years to build. Not all plants can do that, so instead, many California native plants have developed another strategy:
Summer dormancy.
You’re probably familiar with winter dormancy already, in both plants and animals. Many species use spring and summer, which are generally more abundant in resources, to grow and store nutrients away for the long, barren winters. Think Bears, Dahlias, and Oaks.
Summer dormancy is the same principle, but it treats water as the limited resource rather than calories or nutrients. Plants use winter and spring rains to rapidly produce large amounts of vegetation, which immediately get to work photosynthesizing and producing energy for the growing plants. As the season progresses and temperatures heat up, plants begin to “calculate” the cost:benefit ratio of their aboveground vegetation. Many CA natives do the calculus and conclude that killing off and reincorporating their foliage into belowground nutrient stores is the best way to survive, so that's exactly what they do.
Aboveground vegetative structures begin senescing (controlled death) their water-expensive stems and leaves, scavenging any proteins, chemicals, and resources that they can, and sending them to underground storage structures. Suddenly, your beautiful monkeyflower looks like shit! Your sage is clearly dying! And your deergrass must be beyond saving!
But now you know what’s actually happening: Native plants are doing what they evolved to do. They conserve resources, survive the hard times, and come roaring back with the rains. You can cut back dead foliage to reduce fire risk and improve visual appearance, but please remember that many spent flowerheads are full of seeds! And those seeds feed native birds and mammals, in addition to spreading more beautiful flowers throughout your beds. So, if you’re going to deadhead, do so consciously, and maybe shake the heads around your garden a bit to spread the seeds.
I hope this post helped you understand why your garden might look the way it does right now. You’re not a bad plant parent because your garden is brown, and your garden isn’t doomed. It’s just summer, and the plants want to get inside as much as you do!