Every season brings with it specific tasks to keep your garden looking its best. Here are five tips to keep in mind for your garden as we close out summer and head into fall.
Refresh Your Annuals
By this time of year some of your annuals may be looking overgrown or leggy. Replace your summer annuals with fresh, cold-tolerant annuals such as mums, calibrachoa, petchoa, celosia, and ornamental peppers and grasses. They will look great all the way to the first frost, while some annuals, like pansies, and ornamental kale and cabbages can even handle a light snow.
Tropical annuals, such as palms and alocasias, can be brought indoors once nighttime temperatures dip down to the low 50s. Just make certain to debug them with a soapy water solution or insecticidal soap before bringing them indoors.
Plant in the Fall
Yes, you can absolutely plant in the fall! In fact, the cooler air temperatures combined with the warm soil create the perfect conditions for plants to set root in the fall. Trees and shrubs can be planted up until the ground freezes, while most perennials should be planted by the end of September. Consider adding Espoma Biotone Starter with mychorrhizae and pinching back any buds or flowers to help promote root growth. If the plant is root bound, tease or score the roots so they can spread out into the soil easier.
Early fall is also a great time to divide and transplant your spring blooming perennials, such as hostas and daylilies. Fall blooming bulbs, like the fall crocus, can be planted now, while spring blooming bulbs, such as daffodils and tulips, should wait until temperatures cool into the 50s.
Watering & Mulching
New fall plantings will still need to be watered thoroughly and deeply at the base of the plant through November. However, as temperatures cool, plants do not need to be watered as often. Check one inch below the soil line regularly to determine watering needs. Applying 1-2 inches of pine fines or leaf mulch to perennials and 2-3 inches of hardwood mulch to trees and shrubs will help retain moisture longer. Makes certain to keep mulch way from the crown and lower branches of the plant. And no volcano mulch around trees!
Pruning & Fertilizing
Pruning and fertilizing stimulate new growth and this new growth may not be hardy enough to make it through the winter. Wait to fertilize roses again until spring so as not to promote tender new growth. For many shrubs it’s best to wait until you see new growth in the spring. We encourage most pruning to be held off until spring as many flower heads and grasses add fall and winter beauty to the garden, as well as shelter for beneficial insects and food for birds. Do not prune spring flower shrubs, like lilacs, that set their buds the year before. Those should only be pruned no more that 2 weeks after they bloom in spring.
Common Fall Problems
Some plants such as herbaceous peonies, tall garden phlox, monarda, hostas lilacs and ninebark are susceptible to powdery mildew. It is best to prune back these plants that have been affected, throw away the debris (do not compost), and clean your tools thoroughly to prevent it spreading to other plants. You may find the leaves on trees changing early due to the environmental stress of a hot, dry August. Leaf scorch turns the leaf edges brown when there is not enough water or the roots aren’t sufficient to support the leaves. Some trees, such as river birch, shed their leaves when stressed to conserve energy.
