The Ornamental Garden in November
Now that November has arrived, the autumn leaves are past their peak and the ornamental garden is entering a state of dormancy. Does this mean it’s time to put away the gardening tools? Not really. The gardening season doesn’t truly end in the central part of Virginia until the ground freezes, which may not happen until December. Meanwhile, there’s a lot to be done to prepare the garden for winter.
GENERAL FALL TASKS TO COMPLETE IN NOVEMBER
Here’s just a sampling of tasks to be completed this month:
Drain and store water hoses, sprayers, and wands. Leaving them outdoors all winter is never a good idea. Don’t forget to drain irrigation systems as well as any outdoor spigots that are not frost-proof.
Shut down and winterize water features. Fountains that are full of either standing or running water risk being damaged in freezing weather. Vessels with pumps should be emptied and stored and the pumps drained, dried, and stored as well.
Remove dead or dying plant matter from ponds. Decomposing organic matter can deplete oxygen in the water, potentially killing pond fish over winter. For smaller ponds, place netting over the surface to catch falling leaves. For general information on water garden maintenance and advice on overwintering pond plants, see Virginia Cooperative Extension (VCE) Publication 426-042, Winterizing the Water Garden.
Clean and store lawn ornaments such as portable trellises, figurines and other decorative ornaments. Also, don’t leave empty flowerpots, particularly clay ones, outside. They can be damaged from freezing and thawing cycles.
Dig up and store tender bulbs that you didn’t get around to digging up in October. University of Maryland Publication HG105 on Overwintering Tropical Plants gives good advice on how to store caladium and elephant ear (Colocasia spp.) bulbs. It also provides guidance on how to overwinter tropical plants in general.
Continue watering evergreens until the ground freezes. They will survive winter’s freezing temperatures far better if well hydrated before cold weather sets in. In particular, they are better equipped to ward off winter browning of foliage from drying winds.
Collect soil samples to test for pH and nutritional levels. Don’t guess what your soil needs. If the soil test indicates your soil pH needs to be raised or lowered, now is a good time to apply either lime or sulfur as needed.
Remove the spent flower heads of chrysanthemums to tidy up the plants. However, leave the stems standing. They should not be cut back to the ground until late winter or early spring. The dead tops help protect the crown of the plant in cold weather.
Remove and dispose of diseased foliage from roses, peonies, irises, daylilies, and any other plants that are subject to fungal leaf diseases. Do not put the diseased foliage in your compost pile. Bag it and put it in the trash.
Apply a layer of mulch over the root ball of roses after the first hard frost (below 24°F).
Mulch flower beds after the ground freezes to prevent injury to plants from frost heaving.
Plant deciduous trees and shrubs now. Planting them during cool autumn weather allows them to become established before next summer’s brutal hot weather arrives. Prepare the planting site by loosening the soil well beyond the drip line of each plant. Dig a hole that is two to three times wider than the diameter of the root ball but no deeper than the height of the root ball. Remove any wires, ropes, and non-biodegradable material from the root ball before back filling the hole. After you finish back filling, apply about 3 inches of mulch over the site but don’t let the mulch touch the trunk of the plant. Leave a 2” to 3” gap between the trunk or plant stem and the mulch. Water the plant well but not to the point that the soil becomes soggy.
Finish planting spring bulbs. VCE Publication 426-201, Flowering Bulbs: Culture and Maintenance, recommends a planting depth of 2-1/2 to 3 times the diameter of the bulb. In other words, if your bulb is 2” in diameter, plant it 5” to 6” deep (that’s from the top of the soil to the bottom of the bulb). While some bulbs can tolerate some shade, most of them do best in a sunny site that drains well.
Dig a hole now if you intend to buy a live Christmas tree for planting out after the holidays. It’s much easier to prepare the planting site now before the ground freezes. Otherwise, you may find the task very difficult in the dead of winter.
Install tree guards or chicken wire around the trunks of vulnerable young trees and woody shrubs to discourage rabbits, deer, squirrels and voles from nibbling on the bark.
Rake up leaves that are falling into flowerbeds. Unless they are chopped into smaller pieces, they can mat down, which can harm overwintering plants.
Clean and oil gardening tools and store them in a dry place over winter.
MOVE ESTABLISHED SHRUBS AND TREES WHILE THEY ARE DORMANT
It’s no fun digging up established trees or shrubs, but it is sometimes necessary to do so. Late fall is the perfect time for this task. This undertaking is not for the faint of heart, particularly if the plant is on the large size. Moving such plants normally require root pruning when the plant is dormant and needs to be done before bud break in spring if you are planning to relocate the plant in fall. The Clemson Cooperative Extension’s Home and Garden Information Center Publication HGIC 1055 offers sound advice on how to transplant established trees and shrubs. It’s important to make sure the root ball is large enough to accompany ample fibrous and feeding roots to help the plant make a full recovery from the move. The HGIC publication includes a useful chart recommending the diameter and depth of the root ball needed for this purpose.
GARDENING FOR THE BIRDS
Don’t get overly aggressive about cleaning up your spent ornamentals, particularly the ones with seed heads. Leave them in place as a source of food for foraging birds over winter. Seeds from cone flower, aster species, black-eyed Susan, sedum, Joe Pye weed, coreopsis, globe thistle, and even zinnias and marigolds will be welcomed by a variety of bird species.
Clean out bird nesting boxes to prevent mites and avian diseases from overwintering in them. This job should be done with the use of garden gloves and a face mask (to avoid inhaling any of the debris). After removing the old nesting material, scrub the inside of the box with a solution of one part bleach to nine parts water. After the box dries, dust it with a wildlife-safe fungicide, and reassemble it promptly so that overwintering birds can use it for shelter.
If you decide to feed wild birds, now is the time to set up bird feeders. For advice on the food preferences of common bird species as well as the type of feeders to use, see VCE Publication 420-006, Feeding Wild Birds.
HOW TO OVERWINTER CONTAINER GARDENS
Container gardens are very popular these days. But, when temperatures fall, you are faced with the dilemma of what to do with the plants, particularly perennials. If you planted perennials in a container garden, you may be tempted to leave them outdoors all winter. But before you do that, make sure both the plant and the container can withstand freezing temperatures. First, check the hardiness zone for your containerized plant. The central part of Virginia is in USDA zone 7. If your plant is rated as hardy in one or two colder zones (in our case, zones 5 or 6), it will probably overwinter just fine outdoors with protection.
Make sure the pot is frost-free. The more porous the container, the more likely it will crack during freezing weather. For example, untreated terra cotta absorbs water, which will expand when frozen causing the pot to crack.
The more soil you have in the container, the better insulated the plant roots will be. If you’re not sure there’s enough soil in the pot, try placing the entire container into a larger one and filling in the space between the two pots with soil or mulch.
Place the potted plant in a sheltered place out of drying winter winds.
If this approach doesn’t appeal to you, other options include the following:
- Remove the plant from the container and plant it in your garden. This will solve the immediate problem while you consider a permanent home for the plant next spring. Mulch the plant with a 2” to 4” layer of mulch after the ground freezes. It’s important to mulch after the ground freezes to prevent the plant from heaving out of the frozen soil.
- Plant the perennial, container and all, in the ground before the ground freezes. Cover it with a layer of mulch after the ground freezes. The mass of soil surrounding the pot will help protect it and the plant roots from freezing.
- Move the potted plant into a cold frame and monitor the temperatures to prevent the plant from overheating on warm days.
- Move the container into an unheated garage or basement where it can get some light. Keep the plant barely watered, just enough to keep the root ball from drying out.
Continue to inspect indoor plants closely for insect pests such as aphids, mealy bugs, mites, scale, spider mites, thrips, and whitefly. Treat for them as soon as possible. Otherwise, they may spread to other plants causing you a lot more work to bring them under control.
Reduce or hold off on fertilizing houseplants until spring. Winter is their time to rest.
Start forcing paperwhite Narcissus bulbs now
in order to have them in bloom over the winter holidays. Paperwhites don’t require any period of chilling and are very easy to force. Once planted, they will bloom in about 5 to 6 weeks, according to VCE Publication HORT-76 on forcing flower bulbs for indoor bloom. This publication provides excellent graphics and clear instructions on forcing bulbs. It also provides a useful listing of bulbs commonly forced into bloom and projections on the number of weeks they should be planted in advance of flowering.
Start Amaryllis bulbs for bloom over the winter months. One of the easiest and most satisfying of bulbs to force, an Amaryllis will begin blooming within 6 to 8 weeks on average after it is planted. Like paper whites, these popular bulbs don’t need to be chilled in advance of forcing. The bulbs generally come with instructions for forcing them. However, if you don’t have instructions, refer to VCE Publication HORT-76 for information on how to force them.