Design trends

Tips for Gardening in Clay Soil

California Fuchsia tolerates clay soil.

Soil is a wonderful thing. It grows our food, anchors our trees and provides a foundation under our feet. But it sure can be hard to work with when it’s not the soft, crumbly loam that many plants prefer. It’s amazing that anything grows in some of the soils here in the Santa Cruz mountains. Some folks near Quail Hollow garden in an ancient sea bed of sand and there are others who have such heavy clay in their gardens that you wonder how anything survives.

I used to live up under the trees in Felton where the soil was heavy clay. Then I lived in Bonny Doon and my garden was gritty sand. Both soils have their challenges but I think clay soil is the hardest to deal with. Soil that does’t drain quickly during the winter is especially challenging. Where’s that perfect loam when you need it?

Some soils in Boulder Creek require a pick ax to break up enough to plant. Sound familiar? Although rich in nutrients, clay soil requires compost to provide the environment necessary for beneficial microbes, worms and other critters could do their work and aerate the soil. A thick layer of mulch spread over the soil helps to preserve soil structure and prevent it from packing down again. Do not add sand to amend clay soil. You’ll just create cement.

There are plants that are tolerant of clay soils but California native plants won’t tolerate standing water for any length of time. They’ll die from either root rot or suffocation as saturated soils prevent oxygen from getting to plant roots. You can plant on a slope where the water is unlikely to saturate the ground around the plant.

Search for native plants that will survive slow draining soils at Calscape- https://calscape.org. Using the Advanced Search tool you can see which plants tolerate different conditions. Enter your address to find plants for all kinds of sun, moisture and drainage situations. I found 48 plants native to Boulder Creek that tolerate slow drainage on the website. From ceanothus to manzanita to California fuchsia to Douglas iris you’re sure to find plants that look great and perform well.

There are plants from similar environments in other parts of the world that would also do well if you garden in heavy soil. One of my favorite trees for these conditions is the strawberry tree. Also hackberry, ash, gingko and paperbark trees work well also. Shrubs to try include flowering quince, bottlebrush, Australian fuchsia, smoke tree, escallonia, pineapple guava, mahonia, osmanthus, Italian buckthorn, elderberry and vitex. Easy perennials for clay soils are yarrow, bergenia, carex grasses, fortnight lily, coreopsis, echinacea, nepeta, salvia, teucrium and verbena to name just a few.

If you’re not familiar with some of these plants it’s easy to see what they look like by Googling images. It’s what I do to see a plant full grown and not just a line drawing or a close-up of the flower.

So you see, there are plants that will be successful even in heavy, clay soil, you just have to pick the right ones.

Design trends

What to Do in the September Garden

Grevillea lanigera is a good low water groundcover that attracts hummers

Summer is winding down. It’s still warm during the day but the nights are cool and there’s less and less daylight hours. The soil is still warm so it’s the perfect time to start thinking about planting. Like the saying goes, “gardening is a way of showing that you believe in tomorrow.”

Gardening makes us learn new things. If you water less frequently, some plants may decline or even die eventually. Remove those that do and replace them with plants that will thrive with less water.

Fertilize shrubs lightly one last time if you haven’t already done so last month. All shrubs, especially broad-leaved evergreens such as rhododendron, pieris, camellia, hebe, need to calm down, stop growing and harden off to get ready for the winter cold. Some plants have already set next year’s buds.

Roses especially appreciate a bit of fertilizer now, encouraging them to bloom another round in October. To keep them blooming make a habit of pinching and pruning off old flowers. Always cut back to an outward facing branchlet with five leaves. There are hormones there that will cause a new rose to grow much sooner than if you cut to one with only three leaves. You can always cut lower on the stem if you need to control height.

Deadhead flowering annuals and perennials in the ground as often as you possibly can. Annuals like zinnias and cosmos will stop blooming if you allow them to go to seed. The same is true of repeat blooming perennials like dahlia, scabiosa, echinacea and lantana. Santa Barbara daisies will bloom late into winter if cut back now. These plants know they’re on this earth to reproduce. If they get a chance to set seed the show’s over, they’ve raised their family. Try to remove fading flowers regularly and you’ll be amply rewarded. If you want to start perennial flowers from seeds this is the time so that they’ll be mature enough to bloom next year.

Now through October, divide summer blooming perennials like agapanthus, coreopsis, daylilies and penstemons that are overgrown and not flowering well. You can also divide spring blooming perennials like candytuft, columbine, astilbe, bergenia and bleeding heart but sometimes they don’t bloom the first spring afterwards due to the energy they use re-establishing themselves. If you’re on a roll out in the garden, go for it now.

It’s still a little hot to plant cool season veggies starts in the ground. They appreciate conditions later in September when the soil is still warm but temps have cooled. It is OK to plant seeds of beets, carrots, spinach, arugula, mustard, leeks, onions, peas, radishes and turnips.

If you aren’t going to grow vegetables in the garden this fall consider planting a cover crop like crimson clover after you’ve harvested your summer vegetables.
It’s never too soon to start planning for erosion control in those areas that caused you problems during last spring’s storms.

Cut back berries vines that have produced fruit. Canes of the current season should be trained in their place.

Spider mites are especially prolific during hot, dry weather. Sometimes you don’t even know how bad the infestation is until all your leaves are pale with stippling. Periodically rinse dust and dirt off leaves with water. Spray the undersides of infected leaves with organics like insecticidal soap switching to neem oil if they build up a resistance to one of the pesticides.

Now that you’ve taken care of your chores reward yourself by adding perennials to your garden for color in late summer through fall. Take a look at the garden areas that aren’t working for you and replant. Good choices include aster, chrysanthemum, coreopsis, and gaillardia. Abutilon (Flowering Maple) come in so many colors that you probably need another one in your garden. Petite Pink gaura looks fabulous planted near the burgundy foliage of a loropetalum. Don’t overlook the color of other foliage plants like leucodtendron ‘Jester’ or Orange Libertia in the garden. A favorite ground cover that hummingbirds love is grevillea lanigera. Consider it for those hot areas.

One last to do: Make a journal entry celebrating the best things about your garden this year.

Design trends

California Natives for Containers

Native Western Azalea are so fragrant you can enjoy their scent from a distance.

Adding California natives to my collection of container plants has been a goal for a long time. Besides attracting birds and wildlife to the garden they use less water than most container plants plus they are beautiful. Since I have limited ground to garden I mostly have containers and have been quite successful as long as I match the sun or shade to the right plant. You’ve heard it before: “Right Plant, Right Place”
So here are some tips on native plants that do well in containers.

At my front entry that gets morning sun only I have a huge coral bells (Heuchera micrantha) that started out as a cutting wrapped in wet paper towels that a neighbor had found growing at the edge of the forest nearby. It loves it here. Other plants like salvia would not be happy there at all.So it’s definitely the right plant for the right place.I ’ll have to divide and transplant it next spring but it blooms for such a long time and the hummers love it so I never want to disturb it.

Gardening in containers is easy. You can control the soil, water and light and the gophers can’t undermine your efforts. There are a lot of California native plants that do well in containers and I’m going to place them where both the birds and I can enjoy them.

For some of my largest containers I’ll choose from natives like Western Azalea (Rhododendron occidentale), Deer Grass, Chaparral Pea or Giant Chain Fern. Any of the taller growing ceanothus and manzanita would look great too by themselves or combined with smaller growing plants.

For small to medium containers I can use Conejo Buckwheat, Hummingbird Mint, Penstemon heterophyllus, Verbena de La Mina, Mimulus, Woolly Blue Curls or Coastal Daisy, These combine well with colorful Lewisia, Dog Violets or Wild Strawberry.

I might combine a madrone with a Canyon Gray Coastal Sagebrush (Artemisia californica) which grows about a foot high and will trail over the side of the container adding beautiful gray color to contrast with the rich green of the other leaves. I also like the combination of California Hazelnut, Deer Fern, Redwood Sorrel and Wild Ginger.

Some of the most dramatic containers utilize the concept of combining a thriller, some fillers and spiller or two. Not all my containers will use this formula but I seem to be drawn to those that do. Plants in nature can be quite random in the way they grow together and still be lovely. Containers need a bit more order to dazzle and direct the eye.

Thrillers act as the centerpiece of a container. They are usually big, bold and beautiful. Giant Elk Clover is one such California native that is an attention getter. Chilopsis linearis (Desert Willow) is another great subject for containers as it is slow growing and beautiful in leaf and flower. Other architectural natives that will catch your eye as the centerpiece of a container are Hardy Hibiscus (Rose Mallow) and Pacific Dogwood. The thriller goes in the center of the pot or if your container will be viewed from only one side it goes in the back.

Next come the fillers. They can be foliage or flowering plants but they should complement and not overwhelm your largest plant. Usually they have a mounding shape and I’ll plant several around the thriller. Good fillers include Heuchera micrantha and Western Maidenhair fern.

The last plants I’ll add are the spillers which are small and will soften the edge of the container. Redwood Sorrel, Wild Ginger and Miner’s Lettuce are good choices. California Fuchsia would look spectacular with its red or orange flowers and grey foliage spilling down the side of my container.

The best overall soil mix for natives in containers sharp sand and horticultural pumice added to a good potting soil. Never use perlite or that puffed up pumice because it will float and look terrible. Happy Container Gardening.

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