Garden Guy: Autumn: A Second Chance To Improve Next Year

By Bruce Bennett

Don’t look now, but Autumn is waiting just around the corner to leap out at us. Sun lovers and beachgoers might greet this news with dismay. However, many might extend open arms to the cooler, more settled weather that autumn brings, especially after this summer’s dry and record-breaking (again) hot weather.

Fire Power
Photo by landscapeplants.oregonstate.edu

A growing number of gardeners are looking toward the autumn months as a second chance to bring vibrant colors back into their flower gardens. 

Changing out tired looking flower containers with plants that withstand cooler temperatures and occasional frosts can provide just what’s needed. 

Autumn is a great time to look to leaf foliage or berries for color without the need for flowers. 

Many foliage plants even develop better color when temperatures drop. 

For example, Dwarf Heavenly Bamboo (Nandina domestica) ‘Fire Power’ (above) never looked better as its fire engine red color develops during the cool autumn temperatures.

Unfortunately, many plants used to renovate autumn garden containers are annuals, plants that do not overwinter in our area (Zone 8). While they sometimes continue growing well into November, they are not frost tolerant. These plants need to be protected when there is some in the frost weather forecast. 

Planting in containers makes this job a little easier. An old sheet, burlap or even bubble-wrap can do a great job of keeping light frost from harming the plants. However, all bets are off if a hard freeze is predicted. At that point, start humming a hymn to the glory of compost.

Swiss Chard.
Photo by plantnebraska.org

Plants slow down as the weather cools and the day-lengths shorten. How full the container looks when planted is pretty much how it will look all season. 

These plants will not grow as vigorously as spring planted ones. Also, watch that you are watering properly. 

Water less in autumn especially as it deepens. Fertilizing in fall is likely unnecessary. Some colorful annuals to choose from include the familiar Mums, Flowering Kale, ‘Bright Lights’ Swiss Chard (at left), Marigolds, Sunflowers, Celosia, Mexican Sunflowers and Zinnias.

Fireworks- Photo by plants.ces.ncsu.edu

Another, more permanent way of adding touches of autumn to the landscape is by planting perennials, shrubs and trees with an eye for fall color and texture. 

Goldenrod/Solidago ‘Fireworks’ (at left), Asters, Black-eyed Susans, Pansies, Caryopteris, Upright Sedum, Coneflowers, Blanket Flowers, Coreopsis, Purple Beauty Berry, Anemones, and Paper-Bark Maple just begin a list of colorful possibilities.

Planting in autumn provides many advantages for gardeners. After the chaos of spring and summer gardening, weather cools and things slow down. Rainfall is more than adequate. 

Pests and disease problems tend to disappear. And, most important, the soil is still warm, allowing roots to grow until the ground freezes or gets as close as it can in the greater Seattle area. These conditions benefit both gardeners and plants.

One major obstacle gardeners face is the acquisition of new plants. Larkspur, Cleome, Bread Poppies and other annuals produce many seeds. Perhaps a friend grows them and would be willing to share some seeds. A friend may have a large drift of Black-eyed Susans and is willing to dig a clump for you to divide and plant. 

Gardeners tend to be a friendly group. So ask for seeds, starts and clumps! Also, check out your local garden clubs. Many are now ‘potting-up’ for autumn plant sales. Finally, don’t forget to check with you County Extension and Master gardener programs as well as community college and high school horticulture programs. You may be surprised at what’s out there.

Sale. Photo by lifehacker.com

Leftover plants found in greenhouses, nurseries and big box stores are looking pretty pathetic by this time of year. 

The upside is that ‘the price is right.’ This past weekend, I’ve seen sales of 25% - 75% off regular prices. 

Regardless of what the top growth looks like now, the root systems of perennials are still vigorous and can come back with a vengeance next spring. Take a chance on some of them.

Anemone. Photo by plants,ces.ncsu.edu.jpg

Last year, I picked-up a few Anemone japonica plants that looked so woeful the clerk didn’t even charge me for them. I planted them in October and one-year later, I can look out my office window and see the pink blossoms of Anemone ‘September Charm.’ 

If spending enough time in their growing beds, gardeners may come to the realization that planting a flower sometimes becomes an act of faith.

Have fun in the garden this autumn. As a former college literature instructor, I can recall that English poet, John Keats, called autumn the "season of mists and mellow fruitfulness". 

For me, it’s also a most excellent time to move outdoors, for possibly the final time this year, smell autumn in the air and do a bit of considered planting, pruning and dreaming of next year glories. Happy gardening all!

Bruce Bennett, Garden Guy

Contributing garden columnist, Bruce Bennett, is a Washington State University WSU Certified Master Gardener, WA Certified Professional Horticulturist and public speaker. 

If you have questions concerning this article or care to suggest topics of interest for future columns, contact Bruce at gardenguy4u@hotmail.com.

Q/A

Question: Hey Garden Guy – tell this new homeowner about dahlias. Do I leave them in the ground or take them out? Thanks!

Answer: Hello, grasshopper. I trust you are enjoying the late summer and autumn displays being put on by dahlias at the moment. In the Northwest, the tubers of these plants can be left in the soil for a years. 

Over-winter them by covering the dead plants with evergreen boughs, bark mulch, etc. If the dahlia variety is one that you really like, lift some of them, brush off any extra soil, dust with a bit of sulfur and store in a container of perlite, vermiculite or simple slightly damp sawdust. 

Check them once a month for rot, desiccation, and other problems. If you have more than one variety, write the name in magic marker on the tubers. Replant when the soil warms a bit, say, May. Protect the new shoots from slugs and snails. Best of luck! G.G.