September through October is a great time to plant. The cooler air temperatures bring less stress on plants while the warm soil temperatures are ideal for roots to grow. Everything from deciduous trees and evergreens to shrubs and perennials get a head start on root growth when planted in the fall. This is also a time to prepare gardens for winter but knowing what to do and when will improve the health and beauty of your garden. Read on for our dos and don’ts guide to fall gardening.
General Dos & Don’ts for Fall Gardening
- Use Espoma Bio-Tone to support plant growth for fall plantings.
- Have tools ready before you start (I.e., amendments, mulch, shovel, ruler, garden fork and knife).
- Use clean equipment — disinfect knives or scissors with rubbing alcohol to avoid spreading disease.
- Tease the roots to encourage growth into the surrounding soil.
- Add a 1”-2” layer of pine fines or leaf mulch to perennials and 2”-3” layer of hardwood mulch to trees and shrubs.
- Use plant fencing to protect bark and stems from rabbits.
- Use your mower or a shredder to make your own leaf mulch for roses, a compost pile, garden mulch in landscape beds and edible garden beds, or spread thinly on the lawn to decompose over the winter.
- Maintain watering of new plantings and existing landscapes until the ground freezes.
- Take photos of your garden to reference and plan for next year.
- Don’t let the mulch touch the crowns and stems of plants — no volcano mulch.
- Don’t plant when soil is too wet — a handful of soil should crumble in your hand and not stick together.
- Don’t plant when the ground is frozen.
- Don’t use diseased leaves or plant parts — they should be raked and bagged, not composted or reused.
Trees & Shrubs
- Plant trees up until the ground freezes.
- Use a trunk wrap to protect young tree bark from cold and pests.
- Dig a sloped planting hole three times the width of the potted tree.
- Prune low hanging branches in traffic areas or near signs and power lines for safety reasons.
- Don’t plant shrubs deeper than they are in the container.
- Don’t remove crossing, dead, and diseased tree and shrub branches until after the leaves fall.
- Don’t remove water sprouts, suckers or shoots that form at the base of the tree until late winter during dormancy.
- Don’t prune flowering trees and shrubs until right after they bloom in late spring.
- Leave the flowers on Hydrangeas through winter to add texture to the barren landscape.
- Prune arborescens varieties to 6”-12″ (optional).
- Don’t prune any of the serrata, quercifolia or macrophylia varieties until spring and only after new growth appears.
- Don’t leave potted hydrangeas outdoors.
- Plant perennials and ornamental grasses by the end of September.
- Divide spring blooming perennials such as Amsonia, Daylily, Geranium, Hosta, Iris, Peony, Fillipendula, Cimicifuga.
- Cut back plants such as Herbaceous Peony, Monarda and Tall Phlox that are prone to powdery mildew.
- Cut back plants that aggressively reseed, such as Sweet Autumn Clematis.
- Leave spent Allium, Coneflower, Black-eye Susan flowers and ornamental grasses for winter interest and wildlife food and shelter.
- Cut back Hostas and Daylilies that attract garden pests in the winter.
- Leave foliage on Butterfly Bush, Russian Sage, Asters, Foxglove, and Mums to insulate the crown of the plants over winter
- Don’t cut back Caryopteris and Fallopia until spring.
- Don’t divide late summer and fall blooming perennials until spring.
- Don’t divide perennials on very hot days as the heat of the sun can be stressful to the plants.
- Don’t divide Baptisia, Dictamnus, Echinops, Dianthus, Poppy, and Milkweed as their roots are not conducive to it.
- Don’t divide Asters, Chrysanthamums, Rudbeckia, Boltonia, Monarda, Echinacea, Helenium, Gailardia, Grasses, Helebores, Stachys, Sedum, Plumbago, Tricyrtis and summer blooming Alliums until April.
- Don’t divide Dicentra, Allium, Primula, Dodecathion, Tradescantia and Mertensia until dormancy or after bloom.
- Protect grafted Roses such as Hybrid tea, floribunda, or grandiflora roses from the cold.
- Leave shrub roses such as Knock-Out, Oso-Easy, and Flower Carpet alone as they are winter hardy.
- Dispose of any diseased leaves.
- Apply a mound of compost, shredded leaves, mulch or topsoil over the base of grafted roses.
- Use a ring of chicken wire to keep protection material contained.
- Don’t cut back Roses as it encourages new growth that will not withstand winter.
- Don’t restrict air circulation with the use of Styrofoam cones — on sunny winter days it can heat up enough inside the cone to cause the rose to break dormancy.
- Plant flower bulbs and garlic bulbs when nighttime temperatures drop into the low 50s up until the ground freezes.
- Plant bulbs three times their height and 3″ apart with the point side up or on it’s side.
- Add a mix of leaf mulch or Growing Place Garden Compost to clay soil when planting bulbs.
- Mix Tulip bulbs in with daffodils, grape hyacinth (Muscari armeniacum) and Allium to deter animals from digging them up.
- Plant bulbs near other perennials to camouflage the bulb foliage as it dies back.
- Choose a variety of bulbs that bloom from late winter to very late spring.
- Divide bulbs when they produce more leaves then flowers.
- Don’t cut back bulb foliage until it is limp and yellow and when the plant’s energy has been restored to the bulb.
- Don’t use a cylindrical tool for planting singular bulbs – it doesn’t allow space for the roots to grow.
- Don’t plant bulbs too shallow as this will cause them to emerge too early in spring and be susceptible to winter damage.
- Don’t be discouraged by deciduous trees – very early spring bulbs will bloom before the leaves bud out.
- Don’t plant Tulips deeper than 10″.
- Use cold tolerant plants such as grasses, mums and cabbage in your containers to enjoy many more weeks of color on your porch or patio.
- Use collections from your garden such as spent coneflowers, allium, hydrangeas as well as twigs and pine cones to add fall interest to containers.
- Bring smaller terracotta, plastic, wood and thin-walled ceramic pots into your garage or basement for winter storage.
- Remove soil in your larger pots to clear drainage holes.
- Flip over containers with lips, curves or depressions and store under eaves or a covered porch.
- Place ornamental pottery on top of pot feet, bricks or pallets and cover with a tarp if left outdoors for winter.
- Don’t leave larger pots sitting directly on soil.
- Don’t leave more than half of the soil in high-fired glazed containers if they are out in the elements.
- Don’t worry about concrete and cast iron containers being left upright outdoors if they are cleared of soil.
Fall is a great time to plant! This weekend we have two talks to get you inspired. At 11am it’s Bulb Basics both in the ground and in containers. At 1pm learn What NOT To Do In The Fall Garden. We’ll also talk about dividing perennials and what you can do in the fall to get a jump on spring.
No registration required. Free.
Saturday, September 17, 2022 – Naperville
Sunday, September 18, 2022 – Aurora
11 am – Bulb Basics
1pm – What NOT To Do In The Fall Garden