LONG LASTING ANNUAL FLOWERS
In early October two annual flowers stand out for their late season performance: begonias and impatiens. Beds and baskets are still in full bloom. Although well known for their shade tolerance, begonias and impatiens can also be planted in sunny locations. Other annual flowers, like marigolds and geraniums still have a moderate amount of bloom. Petunias only have a few scattered flowers. This is a good thing to remember when you are planting beds and baskets next spring.
Why do some annual flowers continue to bloom later in the season? My guess is it is largely due to day length. Most annual flowers are “long day plants” Their flowering is triggered by the long days of late spring and summer. When the days become shorter than the nights, they quit blooming. Impatiens and begonias are apparently “day neutral plants”. Day length does not affect their flower formation.
We are familiar with “short day plants” such as chrysanthemums and perennial asters which begin blooming as the days get shorter in the fall.
So if you want more color this time of year, plant more begonias and impatiens next spring.
Because of heavy rainfall, Northwest soils are quite acid. Many plants like acid soil but most prefer a more neutral soil condition. Most lawns, fruits, flowers, bulbs and vegetables will benefit by a yearly application of lime or similar soil sweetening products which contain calcium. Up to 5 pounds per 1000 square feet can be applied. Rhododendron, Azalea, Camellia, Heather, Mountain Laurel, Magnolia, Holly, Dogwood, Andromeda, Leucothoe, Blueberry and Raspberry are some major plants which prefer acid soil and should not be treated with lime.
FALL WEED CONTROL
Fall is an ideal time to control weeds because they are actively sending food to their roots for storage. The weed killer gets translocated clear to the roots along with the food.
Lawn weeds can be controlled with a granular weed and feed product if you have not fertilized your lawn yet this fall. Liquid lawn weed killers are most efficient when you have only a few weeds.
Granular weed preventing compounds such as Preen (and similar products containing Trifluralin) can be applied around perennial flowers to prevent most of those winter weeds which begin to sprout about now.
This is an excellent time to spray wild blackberry and other woody plants with brush killer containing triclopr. Roundup or other weed killers containing glyphosate will kill most other weeds growing in unplanted areas and around trees and shrubs. It is especially effective in killing unwanted grass. Roundup will not damage trees and shrubs as long as you keep it off their leaves.
After you have removed or killed weeds growing around trees and shrubs, Casoron granular weed preventer can be applied. It will prevent almost all weed growth for a year. Another way to prevent weed growth around shrubs and trees is to mulch with bark dust or other materials. Most weed seeds require light to germinate. Mulch prevents light from reaching the weed seeds near the top of the soil. Woven fabric mulch also blocks light and creates a physical barrier to weed growth.
THIN STRAWBERRY BEDS OR START A NEW ONE
After two or three years strawberry beds become so thick with plants that they produce less and less fruit. Thin out excess plants so there is at least 6 inches between plants. Remove the oldest and largest plants and leave the new runner plants. These young plants can be moved to new locations in the bed or moved to start a new strawberry bed. The youngest plants will produce the most fruit next year. Now is a good time to fertilize strawberries. I usually use a general purpose 16-16-16 fertilizer. But almost any fertilizer is effective including organics and lawn fertilizer.
FERTILIZE TREES AND SHRUBS
Trees and shrubs can be fertilized in the fall. Actually, anytime between now and new spring growth is a good time to fertilize woody plants. The best fertilizer for trees and shrubs is lawn fertilizer. Remember that most of the water and nutrient absorbing roots of trees and shrubs are located near or beyond the outer edge of the branches.
PLANT SPRING BLOOMING BULBS
October and November are ideal months to plant spring blooming bulbs such as daffodils, tulips, hyacinths, and crocus. This is also a good time to plant summer blooming bulbs such as lilies and allium (ornamental onions). There is better selection if you purchase now even if you can’t plant right away.
It is easy to plant bulbs in pots for mid winter bloom if you have an extra refrigerator. Fill pots 2/3 with soil. Place bbs close together but not quite touching. Cover with soil so just the tips of bulbs show above the soil. Place them in a refrigerator for about 12 weeks. As soon as they start to grow, remove them to a sunny window where they will bloom in about two weeks.
Amaryllis and paper white narcissus bulbs can be bloomed in containers without any pre-cooling.