October Gardening Tips and Tasks

• Practice conservation gardening to support native wildlife through the cooler temperatures. Not all animals migrate to avoid the winter weather -- some animals overwinter (spend the winter months in one of their life stages) here in Maryland. Many of these animals, including pollinators and beneficial insects, require plant debris like leaves, pithy woody stems, and flower stalks as winter habitat. To learn more about creating overwintering habitats in your greenspaces, check out this Fall Actions for Conserving Beneficial Insects (PDF) handout, this webinar on To Rake or Not to Rake, or one of our many Maryland Grows Blog posts about supporting pollinators in the fall and winter.
• If you have the yard space, plant your own tree, or volunteer to care for a tree or support forest conservation. Be a tree steward, because trees have many benefits: they provide shading, cooling, wildlife habitat, carbon storage, erosion suppression, and stormwater absorption. The State of Maryland is aiming to plant 5 million native trees by 2031.

• Flower buds are forming (or are already formed) on spring-blooming shrubs and trees. Examples include azalea, rhododendron, andromeda/pieris, lilac, hydrangea (bigleaf and oakleaf), forsythia, flowering quince, flowering cherry, dogwood, magnolia, and serviceberry. To prevent reducing or removing all of next year’s blooms, don’t prune spring-flowering shrubs now; wait until after they bloom next spring.
• Hardy trees and shrubs stocked at area garden centers can be planted until the ground freezes. The earlier in autumn they are planted, the more time they have for establishment before root growth slows for winter. Don't plant evergreens (conifers or broadleaf) late in the autumn because they're at greater risk of winterburn.
• Carefully examine trees and shrubs prior to purchase to assess quality. With balled-and-burlapped (B&B) plants, remove the twine or wire wrapped around the root ball, and cut away the nylon or burlap wrapping before planting.
• Never carry a tree by its trunk, this can damage the root ball. Instead, always carry them by their root ball or by the container.
• Leaf yellowing on evergreens happens every year as the old leaves shed, but in some years it is more noticeable. Different evergreen species shed old leaves in spring or fall; white pine trees, for example, shed old needles in fall. The pine needles in the canopy interior (closer to the base of the branch) turn yellow and drop off. Shedding can also occur on rhododendrons and other evergreen shrubs, which is normal for this time of year.

Beneficial

• Yellow-faced bee adults are active and foraging for nectar and nesting habitat. Ensure your landscape has late-season flowers to provide nectar. This bee species likes to nest in hollow plant stems. If you prune perennial stems, consider leaving at least 8 to 24 inches of stem in place for nesting habitat. If you need to remove more, consider gathering your trimmings into a pile and leaving them outside instead of disposing of them, allowing any overwintering bees/insects to still emerge come spring.
• Black swallowtail butterfly caterpillars are active and preparing to form chrysalises, where they will spend the winter. Learn to recognize these caterpillars and consider tolerating their feeding damage. They prefer to feed on plants in the carrot family, Apiaceae (carrot, parsley, fennel, dill, etc.).
• Syrphid fly adults and larvae are active. The adults, also called flower flies or hover flies, visit flowers and often look like small bees or wasps due to their body colors and patterns. The larvae are beneficial predators that feed on a wide range of soft-bodied pests, including aphids. Depending on the species, some syrphid larvae will seek shelter in leaf litter as overwintering habitat. Consider leaving some fallen autumn leaves as habitat, especially under flowers where you have seen the larvae.
• Praying mantis adults are active and laying egg cases (called ootheca), often attached to plant stems or shrub twigs. All mantid species in our area are considered beneficial predators and are generalists, eating anything they can catch; do not target and kill non-native mantid species. Support these predators by leaving their egg cases outdoors for fall and winter to hatch naturally in spring; do not bring egg cases indoors, as the warm temperatures inside your home could cause an early emergence of immature mantids that will have no food.
• Florida predatory stink bug adults are active and feeding on a wide range of insect pests. These predators will start searching for overwintering habitat such as wood piles and sheltered crevices. Learn to distinguish this predatory stink bug species from plant-feeding stink bug species. Consider creating a wood/brush pile or leaving fallen logs to provide overwintering habitat.

Pests

• Spotted lanternfly adults may be found feeding on many host plants, especially tree-of-heaven (Ailanthus altissima). If you observe spotted lanternflies, inform the Maryland Department of Agriculture (MDA) by reporting the sighting on their website. These insects are mainly nuisance pests in residential gardens and landscapes, and have not been shown to significantly damage otherwise-healthy ornamental plants. In autumn, adult spotted lanternflies lay clusters of eggs on tree branches and trunks, and just about any outdoor surface (outdoor furniture, tires, walls, stone, etc.). Squish or remove egg masses (once properly identified) by scraping them off into a container of soapy water or alcohol.
• Various types of caterpillars may be found feeding on tree leaves this time of year. Research has shown that this late-season damage is minor to overall tree health, and the management of caterpillars is usually not necessary.
• Fall webworm caterpillars are active and create tent-like silken webbing on the ends of tree and shrub branches. Caterpillar feeding damage is usually minimal, and control is not typically needed. Caterpillars are typically only active through October. Tents can be pruned out or left for natural predators like birds and parasitoids. Do not try to burn any webbed tents. Contact a professional if you would like to prune out a tent you cannot reach safely.
• Large milkweed bugs are active on their primary host plants, milkweeds (Asclepias species). No control is necessary unless you want to save the milkweed seeds for propagation. These bugs are primarily a nuisance pest, and are only present on milkweed seed pods for a short period of time before they migrate south for the winter.
• Boxelder bug nymphs and adults are active and may congregate on boxelder trees, mulch, or in sunny areas of buildings. Adults will seek shelter for the winter, possibly finding their way indoors. This insect does not harm people, pets, or buildings, and does not significantly damage plants, so control is generally not needed. If found indoors, vacuum or sweep up the insects.
• Mexican bean beetle adults are active and feed on the underside of legume leaves (lima beans, snap beans, etc.). Adult beetles will spend the winter months sheltering in plant debris. Pull up and dispose of infested legume plants after harvest.
• Many different cabbage-feeding caterpillars and moths are active. Check host plant leaves (mainly crucifers/brassicas) for signs of feeding damage and for the presence of caterpillars and droppings (frass). Found caterpillars can be removed and destroyed. Remove infested plant debris after harvest to remove pest overwintering sites.
• Striped and spotted cucumber beetle adults are active and chewing holes in leaves, flowers, and fruit. Common host plants include cucurbits, legumes, and tomatoes. Adults spend the winter months in plant debris and soil. Remove infested debris after harvest. In the fall or spring, lightly till the soil to disrupt soil-living life stages.
• Many different social wasp species (like yellowjackets) will seek out sources of sugar this time of year. Keep outdoor food and beverages covered, rake-up and discard fallen tree fruit, and use tight-fitting lids on trash cans. Certain wasps may sting if they feel threatened; avoid swatting or handling any wasps.

• Stop feeding fish in outdoor ponds. They cannot metabolize food easily during cold weather.
• Black rat snakes may still be hatching in October. These harmless baby snakes are not black at hatching but are a light gray with dark brown rectangular markings down the back.
• Feeding deer is not recommended. The practice upsets the size of the local herd, increases their tendency to become pests, and may contribute to the spread of disease within their population.

• Full-size green tomatoes can be picked before a frost and brought indoors to ripen. They ripen more quickly if placed in a paper bag with a banana or apple. The ethylene gas released from the fruit will help to ripen the tomatoes.
• Carrots can be over-wintered in the garden by covering the bed with a deep straw or leaf mulch. Pull carrots through the winter as needed.
• Lettuce, spinach, arugula, and kale can be planted through the middle of the month. Cover these late plantings with a cold frame, temporary greenhouse, or row cover. Be sure to fertilize seedbeds, keep the soil moist, and protect seedlings from pests. The young plants will go dormant and resume growth in spring.
• Discard badly-diseased plants and fruits; don’t till them back into the soil. All other plant waste can be hot-composted (cold composting will not kill plant pathogens, pests, or weed seeds).

Start a compost pile by mixing together spent plants, kitchen scraps, fallen leaves, and grass clippings. Shred your materials with a lawnmower or string trimmer to speed up the breakdown process. Keep twigs, branches, and other woody materials out of the pile.

• Goldenrods and asters are important fall flowers for pollinators. Consider adding one or more of these to your garden -- there are many species and cultivars available.
• Save seeds from annual and perennial flowering plants like zinnias, cosmos, celosia, and butterfly weed to be planted next spring.
• Annual geraniums (Pelargonium) can be overwintered in several ways. Entire plants can be brought inside and grown in a sunny window, or cuttings can be taken from existing plants to root and grow like a houseplant until spring. Cuttings from other annuals, like begonias, salvias, and coleus, also root well.
• Daffodils, hyacinths, ornamental onions (Allium), and other spring-flowering bulbs can be planted now. Plant them in a sunny spot in well-drained soil. Tulip bulbs should be planted from mid-October through November to prevent them from sprouting prematurely.

• Time is running out for lawn renovation or overseeding. Grass seed should be planted by the middle of the month so it has time to establish enough roots before winter dormancy.
• There is still time to apply fertilizer to cool-season lawns like fescue. Look for a fertilizer with zero phosphorus (P) in the N-P-K analysis on the label. Apply according to the lawn fertilization schedule. Fertilizer needs to be applied before November 15 to comply with the Maryland Department of Agriculture lawn fertilizer law.

In the cooler and sometimes-wetter fall weather, harmless toadstools and other mushrooms may be plentiful around tree root systems or in lawns. In comparison, destructive wood-rotting fungi produce growths (sometimes called conks) on tree trunks, the root flare, or on surface roots, where the fungal growth is emerging directly out of the wood. Affected trees may be suffering from extensive wood decay and should be inspected for trunk soundness by a licensed arborist.

• Inspect new indoor plants before purchase. Choose plants that appear to be free of insects and disease and have healthy foliage. Slipping the plant out of its container to look at the roots is recommended. Roots should be firm (not mushy) and able to hold the soil together without being too root-bound.
• If natural light from a window isn't bright enough, consider using grow lights to provide enough light to support plant health.

• Crickets, multicolored Asian lady beetles, boxelder bugs, stink bugs, cluster flies, and other innocuous insects may attempt to enter your home this fall to overwinter. Caulk, weatherstrip, and seal-up all cracks and entry points around the building foundation, vent openings and pipe/wire entry points, windows and window screening, and doorways to prevent insects from coming indoors.
• Many different spiders like jumping spiders, yellow house spiders, wolf spiders may enter homes. They can wander indoors through or around windows, doors, and cracks. Caulk cracks around doors and windows, especially those at ground level. Most spiders are shy and harmless to humans. Normally, they will not attempt to bite unless accidentally trapped or held. They are beneficial by feeding on nuisance insects, and killing spiders should be avoided if possible.
• Drain flies are found primarily in rooms or areas where there are drains, such as kitchens and basements (near floor drains). Drain flies are small, 1/16 to ¼ inch long, delicate and fuzzy. Their fuzzy, moth-like wings make them easy to identify.
• House mice (and sometimes field mice) may be more noticeable around and in homes due to the onset of cool weather. Keep grass and weeds properly mowed around the house and seal all cracks.