The arrival of autumn doesn't mean that gardening season is over. It's actually just the beginning of the number of tasks that need to be done outdoors before winter sets it. Gardening expert P. Allen Smith and power equipment manufacturer STIHL gave me these helpful tips for preparing your garden for fall.
1. Feed the Birds. Help the birds as their food sources dry up, by getting out the bird feeders. Before you fill them, clean them with a solution of one part bleach to nine parts hot water.
2. Bring in Houseplants. When nighttime temperatures drop to around 50 degrees Fahrenheit, it's time to start moving houseplants back inside. Check them carefully for any unwanted bugs. Spray the foliage gently with a garden hose and wipe the leaves with a soft cloth. If you think your plant shows signs of mealy bugs or aphids, use a houseplant safe insecticidal soap and follow the directions on the label.
3. Hydrate your Flowers. The end of the growing season can be hot and dry. These conditions are stressful for plants, particularly if they are in containers. Keep flower pots, window boxes and especially hanging baskets well watered, and mulch your flowerbed to keep moisture in and weeds down.
4. Dig up Summer Bulbs. Before the ground freezes, dig up tender summer bulbs and store them for the winter. As you dig them up, check to see if the bulbs are soft or rotting. A healthy bulb will feel firm, not hollow or mushy. Discard the ones that aren't healthy. If you live in an area with mild winters, you can leave tender bulbs in the ground if you protect them over the winter with a layer of mulch three to five inches deep.
5. Protect Roses. By late summer, cut back on fertilizing your rose plants. Feeding stimulates new growth that could be snuffed out by the cold. After cold temperatures cause foliage to drop, prune the canes back to 36 inches to prevent damage from winter winds, and cover the plants with at least eight inches of loose, well-drained soil, mulch or compost.
6. Add Autumn Sizzle. Add plants to your garden in seasonal colors of fiery reds, warm golds and brilliant oranges. There are new varieties of fall plants such as 'Snowman' pansies that can thrive in temperatures well into the teens to give you weeks of beauty. Traditional annuals such as chrysanthemums, impatiens, and ornamental cabbage are also reliable plants that will add accents of color.
7. Divide Perennials. Transplant and divide perennials in the early fall to renew a plant's vigor, limit its spreading or propagate more plants. Work on a cool, cloudy day to keep plants from drying out. Once the plants are divided, plant them as soon as possible. Transplants do best if they have a few weeks to develop some roots before the ground freezes. Check gardening resources to make sure the variety you move is suitable for fall division before digging.
8. Save seeds. If you have been removing spent blooms to stimulate the growth of more flowers, stop deadheading in late summer so the blossoms can produce seeds. Once the seeds have developed, allow them to dry and then crumble the dried flower heads into a container. Separate the seeds from the debris and put them in a labeled envelope to plant next spring.
9. Plant Spring Flowering Bulbs. The best time to plant bulbs that bloom in the spring such as daffodils, tulips, hyacinths and crocus is from mid-September until the ground freezes. Many bulbs require several weeks of chilling time before they will bloom. As you select varieties, note that they bloom at different times during the spring season; either early, mid or late spring. By selecting a range of flowering times, you'll enjoy a long sequence of color that will last for weeks. Prepare your soil before planting the bulbs. Work compost or other rich organic material into the planting area to a depth of 12-inches. The rule of thumb is to plant the bulbs to the depth of three times the height of their height. For instance, a tulip bulb that is two inches tall should be planted in a hole six inches deep, so the base of the bulb is six inches below the surface, not the point or top of the bulb.
10. Clean up Debris. Clean up leaves, sticks, rocks and other late season leftovers that can harm next year's lawn and harbor pests and diseases over the winter, but leave enough cover and seedheads to provide wildlife some cover and food.
11. Prune Selectively. Fall pruning can stimulate new growth on some trees and shrubs. Tender new leaves won't have a chance to harden off before cold temperatures set in. So focus your pruning activities on dead or diseased branches. Prune those areas before the leaves fall because it is easier to see those areas while the foliage is still on the tree or shrub.
12. Water Deeply. Once the ground freezes in winter, particularly in cold climates, available ground water is locked up and can't be taken in by trees and shrubs. So give your plants a good soaking one last time before the onset of below freezing temperatures. Newly planted or recently transplanted trees and shrubs need special attention and must be well watered to help them survive the winter.