Timely Tips

What to Do September 2024
Weekly Gardening Timely Tips from
Cornell Cooperative Extension of Westchester County

September 16 – 22

Perennials and Flowers: Many spring bulbs may be planted now, except for tulips which are most successful with an early October planting. Consider planting bulbs around ferns, late emerging perennials and other plants that can hide bulb foliage when it withers in late spring. Some annuals and perennials that have gone to seed will “seed around” and produce free plants for next spring if you leave them in place. If you already have enough in your garden, remove spent, seedy annuals and perennials before the seed scatters.

Fruits and Vegetables: For a spring spinach harvest, sow seeds of hardy varieties such as ‘Melody,’ ‘Tyee,’ and ‘Winter Bloomsdale’ or other winter hardy varieties under a row cover now and surrounded with a thick layer of mulch applied when the ground begins to freeze. You may also start them in a cold frame, insulated by mulch around our first hard freeze. They’ll overwinter under the mulch layer for an early spring crop. Keep up with the fruit harvest. Remove overripe, damaged, or diseased fallen fruit which may contain pests.

Trees and Shrubs: Fall is the best time to plant deciduous spring-flowering trees and shrubs such as beautyberry, redbud, serviceberry, summersweet, and more. You may also plant needled evergreens, such as cedar, pine, spruce, and yewthrough the end of the month. Wait until spring to plant broadleaved evergreens, Japanese maples and marginally hardy trees and shrubs. Water any new plantings as needed until there is a light freeze. Contact your local Cooperative Extension for advice.

Lawns: To encourage “deep” rooting of a newly seeded lawn, gradually reduce watering over a few weeks. Allow the soil surface to dry once the grass has filled in enough to obscure most of the ground. Water the newly established turf as needed up until a light freeze. Begin cutting the grass when it is about 4 to 4½ inches in height. Remove no more than one-third of the grass blades so at least 3 to 3½ inches will remain after mowing.

Houseplants: If your plants have practically doubled their size during their outdoors vacation this summer and are not going to fit in their usual space, try to make accommodations for a new place indoors with good sun and airflow. Alternatively, divide or prune them back before you bring them in.

General: The invasive Spotted Lanternfly (SLF) is spreading in the Hudson Valley.SLF is a serious threat to New York agriculture, causing harm to crops like grape vines. SLF can also feed on landscape plants and is a big nuisance in outdoor spaces when it occurs in high numbers. If you plan to travel or have recently returned from a state where SLF is established, be sure to check your vehicle and any items kept outdoors for hitchhiking lanternflies (a flashlight and mirror may be helpful in hard to see spaces). For more information on spotted lanternfly, seehttps://westchester.cce.cornell.edu/horticulture-environment/invasive-nuisance-species/invasive-pests/spotted-lanternflyLearn more about what you can do to help stop the spread https://cals.cornell.edu/new-york-state-integrated-pest-management/outreach-education/whats-bugging-you/spotted-lanternfly/stop-spread-spotted-lanternfly

Last updated September 16, 2024