The end of August is not the time to fertilize roses, hydrangeas, fruit trees or shrubs. Feeding plants at the end of the growing season can stimulate new growth that can be burned by an early frost.
You can continue to feed annuals such as hanging baskets of fuchsias, petunias and geraniums and cut back any leggy plants to encourage more branching and better blooms into the fall season.
Also, just say no to the low mow this time of year as allowing the grass to grow to 3 inches tall then removing just one third of the blade will help the late summer lawn stay green until the fall rains return.
Q. I am confused about St. John’s Wart. I know this to be an invasive groundcover with rather starry-looking yellow blooms. My neighbor has a nice looking shrub that is labeled St. John’s Wort that had similar flowers but also orange berries. It is not spreading in his garden. — P.P., Tacoma
A. Welcome to the fascinating but often confusing world of plant names. St. John’s Wort is the common name of a family of plants called by the Latin genus name Hypericum. There are many species or forms of this easy-to-grow plant and it is the same family of plants that is popular with herbalist as it contains an ingredient to treat depression.
This time of year you will find the shrubby version at nurseries called Hypericum inodorum Pumpkin or “Magic Pumpkin” but it is not related in any way to the edible pumpkin. Instead the name describes the pumpkin-orange seed pods that follow the bright-yellow summer flowers in the fall. Sprigs of this well-behaved shrub provide long-lasting color not just in fall gardens but in fall arrangements as well. New plants like this are a great reason to visit local nurseries in the fall.
Q. Is it too late to move a Japanese maple? Asking for a friend. — R., email
A. Yes, it is either too late or too early. The best time to move trees and shrubs is early spring or mid fall when the soil is neither dry nor frozen. It is possible to add plants to the landscape in August but you will most likely have success if you add plants that have been growing in containers with compressed root balls rather than try to dig up plants in the dry ground with extended roots.
A tip to get the roots to grow deep is to fill the planting hole with water and let the water soak into the bottom of the hole. Then add the new tree or shrub and the roots will follow the moisture down deep into the soil rather than sit on top near the surface waiting for you to water.
Q. Any hydrangeas that I can plant in full sun? I would prefer a hydrangea that stays small and compact as I hope to create a flowering hydrangea hedge along a walkway. — P.L., Tacoma
A. Yes! The panicle hydrangeas and mountain hydrangeas will take full sun and come in a variety of forms. Bobo is a dwarf hydrangea with rounded white blooms, Invincibelle Wee White has flowers that survive late spring frosts and bright sun and the pointed blooms of the Hydrangea paniculata “Little Quick Fire” will start out cream and turn to pink and red as fall arrives. There is a bountiful cornucopia of hydrangeas that you will find at local nurseries now and many of the sun-loving hydrangeas offer fabulous fall flowers.
Marianne Binetti has a degree in horticulture from Washington State University and is the author of several books. Reach her at binettigarden.com.