Pruning Perennials in Fall
Make sure not to cut back green foliage on any perennial plant (include perennial bulb plants). Allow this new growth to die back completely before removing at the end of the season. The perennials need time to convert the sugar sap in the new growth to carbohydrates, which will be stored in the root zone over winter and used next spring to promote new growth!
Fall Gardening Tips
Fall is a busy time for home gardeners and can rival spring as an important season to plant fall/winter annuals, spring-flowering bulbs, perennials, shrubs and trees, and to prepare the garden for winter.
- Preparing the garden for winter involves several important tasks.
- “Lift” (dig up) summer-flowering bulbs right after the first or second frost in November. When the green leaves are dead, begin digging up, cleaning off dirt, dividing (if necessary) and putting into sheltered storage. An unheated garage is a good place where the bulbs can rest over the winter. They can be replanted in the ground or containers next April. Bulbs are tender to extreme cold and will die if left outdoors over the winter.
- Bring tropicals inside that have been growing in containers outdoors during summer. Since they are not tolerant to cold temperatures, tropical plants will have to be kept indoors in order to survive the winter. Take them indoors before the fall frost date, usually no later than the end of October. Spray them with a houseplant-safe insecticide/fungicide about two weeks prior to bringing them indoors and apply a systemic control. Make sure the indoor location has as much direct sunlight exposure for plants requiring much sun.
- Fall and Winter Annuals: For fall color, plant blooming hardy chrysanthemums which will bloom profusely in September and October. A great time to plant chrysanthemums is when their buds are just starting to open. Leave the plants in the ground after they finish blooming and they will come back up the following spring. At the same time, plant ornamental cabbage and kale. Just like their kitchen kin, these plants love cold weather; and their stunning colors (which could be magenta, red, white, pink or purple), will last until February. Lastly, the most popular fall-winter-spring blooming annual plants, the pansies, may bloom through a mild Maryland winter and then bloom profusely in spring. Pansies, however, do not tolerate high temperatures, and will die out in the heat of summer.
- Spring-blooming bulbs such as tulips, daffodils, hyacinths, and crocus should be planted during the fall. Bulbs require a ‘chill’ growth period with soil temps below 50°F for a minimum of 12 weeks in order to provide the stimulus for them to bloom in spring. Most of these bulbs will bloom in early, middle or late April.
- Fall is the best time to plant new perennials, shrubs and trees; or for transplanting existing ones. New stocks of shrubs and trees become available and all of these plants, including perennials, will establish their roots quickly in the still-warm soil of early fall.
Fall Feeding – Shrubs & Plants
Like grass lawns in last month’s timely tip, shrubs and trees are also in need of nutrients in the fall of the year. Leaves of shrubs and trees need feeding in order to restore their health and vigor after enduring the stresses of spring and the heat of summer. These green leaves need nutrients at this time of year to continue to manufacture sugar sap, which will soon be converted into complex carbohydrates called starches that will to be stored in the roots over the winter as a future energy source. This energy source is what promotes the growth of roots, new leaves, flowers and branches in the spring.
Fertilizers should be applied in early fall, when the leaves on deciduous shrubs and trees (plants that lose all their leaves in the fall and are dormant through winter) are still green and active in producing sugar. Evergreen coniferous and broadleaf shrubs and trees should be fed in late spring. Feeding evergreen plants too early in the fall can stimulate new growth on plants that retain their leaves year-round. This new growth will be too tender to tolerate the frosts that come in late fall. Late fall feeding will be at a time when it is too cool to stimulate new growth and evergreen plants will actively take in fertilizer through early winter.
Moving Tropicals Indoors for Winter
For those of you who have tender tropical potted plants sitting outdoors, you must bring them indoors before the first frost. At these low temperatures, your tropical hibiscus, gardenias, mandevilla, and other tropicals will be severely injured if left outside.
You should make a decision as to which plants you want to save and whether you have room indoors for them. Many of these plants need to keep their green leaves through the winter, while others can be kept in a garage location where the temperature may be cold, but would stay above 32° Fahrenheit.
If you have time, spray the plants with a safe insecticide approved for indoor use. Make sure to choose a location where sun is available to plants that require direct or bright indirect sunlight, and shade to those plant that need low light conditions.
You may notice some immediate loss of leaves, primarily from the interior of the plants or base of the branches. This is nothing to be concerned about. Dropping of some leaves is a natural thing for plants to do this time of year. With the diminishing amount of sunlight available to them as the days get shorter, they simply do not need as many leaves as they do during the summer.
Water as needed, allowing the soil to dry out between waterings. To prevent added stress, refrain from fertilizing the plants until next April. The plants will be less active during the winter and fertilizer will stimulate growth at a time when the plant is striving to reduce its overall activity.