DEAR GARDEN COACH: Is it better to cut back my perennials in the fall, or should I wait until spring? I have many ornamental grasses that are beautiful right now, lots of salvias, penstemons and other drought tolerant plants.
I live in Pleasant Hill where we do get some frost.
Clare MacLauchlan, Pleasant Hill
DEAR CLARE: It is not too late to do some fall clean up as the average frost date for Pleasant Hill is usually in the beginning of December. However this is one of those topics where there are different philosophies about how tidy a garden looks during winter.
I am a naturalistic gardener, which means I allow the garden to rest during winter because plants have a role in the broader ecology of the landscape.
Seed heads and fading flowers contribute to wildlife, such as birds and insects, that help keep the garden in balance.
The photographs from one of my favorite books, “Seedheads in The Garden” by Noel Kingsbury and illustrator Jo Whitworth, depict the beauty of winter gardens. The photographs illustrate a quiet time where the silhouettes of grasses, herbs, such as angelica or fennel, and sturdy flowering perennials, such as sea thistles (Eryngium), and hyssop take on a new life when back lit by the lingering sunlight.
Last month I pruned penstemons, salvias, and lavenders by 1/3 to 1/2 their size, and top dressed them with compost to provide additional nutrients.
Spent seed pods from a canna lily create a visual interest in the winter garden, but they also provide food and perching spots for birds and insects. (Courtesy of Patrice Hanlon)
Pruning when blooms are waning and temperatures are dropping gives the plants a chance grow, but not so much that it wastes energy that is needed for next years blooms.
For plants such as fall blooming pineapple sage (Salvia elegans) and Salvia ‘Mexican limelight, I do not prune until late winter when the danger of frost is over. I will top dress with compost. The older foliage will protect the plant from damage due to frost.
Ornamental grasses can be cut back in February; in the winter garden they provide color and movement as seed heads blow in the wind. Many provide winter habit for birds and insects such as lady bugs.
By December, your spring and summer perennials are dormant, but If you look closely you will see things are happening. Perennials continue to live below the soil; they keep a crown of low evergreen basal leaves during the winter.
Cleaning up around plants, but not totally eliminating debris (such as blowing out the entire area) will benefit your garden with additional organic material that add nutrients to the soil, keep plants safe from frost damage, keep weeds from sprouting and provide food and shelter for wildlife.
DEAR GARDEN COACH: Can you recommend blueberry varieties for our area?
Valerie G., Bay Area
DEAR VALERIE: I am going to recommend a good article written by Bethalyn Black for the University of California Cooperative Extension. In her article she explains about chill hours — the amount of time when winter temperatures are below 45 degrees — and recommends high bush and rabbit eye varieties for our area because they are bred to require less chill time. They also have a shorter ripening period than low bush varieties.
The article covers everything from soils to planting and a list of varieties appropriate for our area.
Blueberries need an acidic soil that our clay soils don’t provide, so you’ll probably need to grow them in containers.
Send your gardening questions to thegardencoachBANG@gmail.com.
Published at Wed, 16 Nov 2016 18:00:57 +0000