We have all experienced that “fall is in the air” moment. When we feel autumn just around the corner, it is time to think about transforming our summer containers to reflect the seasonal change.
Making a few key adjustments to your summer containers can enliven any arrangement as we move to fall and beyond.
The basic design elements, as set out in the “Garden Containers” article in the “Ask the Master Gardener” column published in June, can still apply.
But instead of choosing plants to withstand the bright sun and hot temperatures of summer, we now focus on those that will thrive in the cool temperatures, including frost, and lower light levels to come.
Some plants need longer days to bloom and fall can reduce their flower production. These plants can be substituted with flowers and foliage plants which can withstand darker days.
Add some new potting soil with your fall plantings to refresh your soil base; and remember to pair plants with similar light and water needs in the same container.
Some well-worn perennials you have removed from the container may be planted in your garden beds to be resurrected to glorious perfection next year.
Look around your garden in the warmth of summer and pot up a few coral bells, vinca minor, ferns, dusty miller or hardy grasses that can later be transplanted into your fall containers and save you money.
If you want your plants to move through late fall and into winter, consider the cold hardiness factor. Remember that pots are subject to cold and frost not only from the top, as they would be if ground planted, but around the exposed sides and bottom.
Roots are the least hardy plant tissue and easily damaged. The larger the container with more soil surrounding the roots, the better the protection against freezing and heaving.
For the longest-lasting winter plants, choose those hardy to one or two zones colder than in your area. Look on plant labels, ask your nurseryman or master gardener or other reliable sources for zone appropriateness (Catalogs or websites may list these plants under “Fall Interest” or “Winter Container Plants”).
Adding foliage to your fall pots can introduce long-lasting rich color and drama. Coleus and sweet potato vines from your summer containers will look good through early autumn but the first hint of frost will cause their demise.
They could be traded out with the striking leaves of Arum italicum; colorful coral bells (Heuchera); winter flowering heathers (Erica carnea); bergenias (Bergenia cordifolia) with their glossy green leaves that turn to bronzy red; silver sage (Salvia argentea) for a wintry glow; or hardy edible kale or Swiss chard.
Think about adding textures, e.g., twiggy heavenly bamboo (Nandina domestica), or ornamental grasses like black mondo (Ophiopogon planiscapus ‘Nigrescens’) or sweet flag (Acorus gramineus).
Small evergreen plants like Pieris japonica hybrids, golden dwarf Hinoki cypress (Chamaecyparis obtuse ‘Nana Lutea’), holly (Ilex), or dwarf blue star juniper (Juniperus squamate ‘Bue Star’) can anchor your container well into spring.
Some over-wintering berry plants, e.g., winterberry (Ilex verticillate) or beautyberry (Callicarpa bodinieri), could add interest. Come spring, these perennials and shrubs can be planted into your garden.
Chrysanthemums and pansies are often used in fall containers and both add long-lasting color. Although pansies look delicate and tender, they are some of the most cold-tolerant flowers and come in a wide variety of vibrant fall colors.
The key to their success is to start them early when the soil is still warm. If started in soil temperature below 45 degrees F., pansies’ growth will be stunted, and they will produce few flowers.
Planting hellebores with varied bloom times will give winter color from November through early spring. Or tuck in some early flowering bulbs, e.g., snow drops, muscari, crocus or narcissus to make you smile.
Adding elements of fragrance, e.g. from sarcococca (aka Sweet Box), daphne odora, witch hazel (Hamamelis) or scented bulbs will stir your senses as you walk near their pots, whatever the weather.
Inanimate or natural objects, e.g. glass balls, whimsical creatures, rocks, curly willow branches, pinecones, dried hydrangea blooms, ornamental seedpods, gourds, cornstalks or pumpkins can add instant color and texture. Periodic changes can move your container arrangements through fall, into the holidays and beyond into spring with little effort.
Another difference between spring and fall container planting involves plant spacing. In spring, we leave room between plants for growth.
Even though you will likely plant your containers while it is still warm, cool temperatures will begin coming quickly and plant growth will slow or completely stop. For best results, stuff your fall pots as full as you want the finished container to look.
The deeper you go into fall, the less you will have to water, thanks to Mother Nature. But it is a good idea to monitor your plants throughout the seasons, as containers are subject to drying wind and cold.
Check water levels of your plants which are under cover for dryness or those with saucers or poor drainage which might drown the roots. Evergreens in containers are still growing and should be checked often as well.
Fertilizing in fall is often unnecessary. Many slow release fertilizers are partially dependent on temperature and little to no fertilizer will be released as the weather cools.
If you feel fertilizer will be helpful in giving your plants a good start, use an application of a water-soluble type rather than the slow release variety.
Taking time to transform your containers for all seasons enlivens your living spaces both inside and out. Use your gardening instincts and creativity, as well as ideas from your local nurseries, botanical gardens, books and the internet, to find the best combination to complement your home, location and lifestyle. Jump in and get those hands dirty!