Fall is for garden renovations. Here are tips for sprucing things up with new plants
Fall is for planting, so make this the week you replace and renew anything not worthy of your garden space.
Some of the best-looking shrubs and trees for fall color are also problem solvers in the landscape. Barberries, hypericum and spiraea are a few shrubs to replace thirsty rhodies, hydrangeas or azaleas.
When adding new nursery stock to your garden, be sure to soak the roots well the night before you do the transplant operation. Chose a day that is cool and cloudy or plant in the evening, so the patient has time to recover. A 2- to 3-inch mulch on top of the soil will seal in moisture, block weeds and regulate soil temperature.
Q. My neighbor heard you speak at the Bellevue Botanical Garden this summer. She wrote down “no turtlenecks” when you plant something, but she cannot remember what that means. I said I would write to you ask. Thanks. — B.B., Bellevue
A. Ah yes, “no turtlenecks” is not a fashion statement but a reminder not to pile mulch or soil up around the trunk or neck of trees, shrubs and perennials, especially in the fall. Instead feather the wood chips or bark that you use as a soil covering so that it barely makes contact with the stem of a plant but becomes thicker as you move out to the root zone of the plant.
When you mulch or let soil pile up around a tree or shrub this can encourage rot diseases that enter through the bark. It is especially important not to pile mulch up around the trunk of rhododendrons and azaleas because they have shallow roots.
Q. What is the large shrub that blooms in the fall with huge, cup-shaped blooms? It almost looks tropical. I have seen it with white flowers and purple stripes and also with purple blooms that look like roses. It looks a lot like the hibiscus we used to grow in Hawaii. — J.J., Tacoma
A. Aloha, and you are certainly describing the hardy hibiscus sometimes called the Confederate Rose or Rose of Sharon shrub. There are new varieties of hardy hibiscus on the market now with huge blooms on smaller plants and some with purple leaves and gigantic pink flowers. All prefer some protection from freezing weather — either grown close to the house, mulched or, for those with the largest blooms, grow in a container that you can move each fall to a covered patio or porch.
In my Enumclaw garden, a 30-year-old Rose of Sharon hibiscus flowers August through September with no protection as over the years it has adjusted to cold weather. Semi-tender plants can learn to adjust to cold winters if you pamper them the first few years. Friend me on Facebook or Instagram to see images of hardy hibiscus and other colorful fall plants in my garden.
Q. I have a contorted filbert tree with wonderful, twisted branches and long, dangling catkins in the spring. I love it. The problem is branches have been dying back all wilted and I see black bumps that look like a disease on the trunk of the tree. Can this tree be saved? Remember I love it. — D.G., Kent
A. Your true love is suffering from a blight disease that infects Contorted Filbert trees weakened by lack of moisture. My own twisted Contorted Filburt tree became infected a few years ago.
The best cure is to wait for dry weather and cut out all infected branches, even if you leave the tree looking like it was rudely attacked. Then in the spring fresh new growth can emerge without the blight.
Keep the tree watered during droughts but avoid overhead watering. Wet weather can encourage the spread of this airborne disease.
No need to mask up, blights affect trees not humans. My tree survived and I believe yours will too.
Marianne Binetti has a degree in horticulture from Washington State University and is the author of several books. Reach her at binettigarden.com.
Class on bulbs
Marianne will lead a class at 10 a.m. Oct. 2 at Windmill Gardens in Sumner, “Beauty with Bulbs: using bulbs in pots, beds and baskets including how to plant, the best varieties and how to use bulbs as holiday gifts.” To register, go to windmillgarden.com or phone 253-863-5843.