September's cooler weather and moist soils offer ideal conditions for fall planting.

Late summer into early autumn is the best time to divide perennials that bloom in spring and summer.

Plant trees and shrubs, allowing enough time for roots to develop before ground freezes.

Prepare for first frost. Dig tender perennials such as cannas, begonias, gladiolus. Discard tops and store bulbs, corms, and rhizomes in dry peat moss or vermiculite.

Bring house plants back indoors before night temperatures drop below 55F.

Deadhead perennials, and discard dead and diseased foliage to reduce infection next year.

Begin planting spring flowering bulbs in mid-to-late September.

Fertilize Trees and Shrubs after mid-September.

Apply broadleaf weed killers to lawn.

Restock bird feeders and put out fresh water to help birds migrating south. 

Sourced from Morton Arboretum 10/8/2020

https://www.mortonarb.org/trees-plants/tree-and-plant-advice/horticulture-care/fall-gardening-tips

  To plant or not to plant in autumn, that is the question...

Q&A with Pete Linsner, Manager of Plant Production

Did you know that fall is the ideal time to plant trees, shrubs, and perennials? Arboretum expert Pete Linsner explains why new plants dig fall so much.

What can you plant in fall?

Pete: You can plant all kinds of things in autumn, including evergreen and deciduous trees, shrubs, perennials, and ornamental grasses, as well as spring bulbs.

When is the fall planting season?

Pete: Fall officially begins with the autumnal equinox in late September. In general, the fall planting season lasts September through early October.

Why is fall planting so good for plants?

Pete: Plant health often depends on root health, and in the fall, the warm soil encourages root growth until the ground freezes. In early spring, roots begin new growth and continue to develop before the top of the plant begins to develop leaves, flowers, and new stems. This gives fall planted plants an advantage. Their roots are well-established before summer arrives, and are far better equipped to deal with heat and drought.

Is there an advantage to planting perennials and bulbs at the same time?

Pete: Perennials and bulbs can be planted together without damaging established root systems. Instead of digging through plant roots to layer bulbs, a fall gardener can plant everything at the same time. Not only will this prevent transplant shock to sensitive perennials, but it can save you time and energy, as well.

Pete Linsner is Manager of Plant Production at the Arboretum. He oversees our greenhouses and plant propagation program, and selects the plants offered at our annual plant sale.

Sourced from Morton Arboretum 10/8/2020

https://www.mortonarb.org/trees-plants/tree-and-plant-advice/horticulture-care/fall-planting

At The Morton Arboretum, we plant specimens in our botanical collections in both the spring and fall. With the usual generous spring rains in the Chicago area and the long growing season ahead, most people think of spring as the preferred planting season. Unfortunately, sometimes that generous rainfall prevents us from getting into the site as it makes the soil too wet to plant. Also, in many years, we have a "shortened" spring season and jump right into the hot, dry summer. It is hot, dry conditions beginning too rapidly that can injure newly-planted specimens.

So fall season planting (mid-August through mid-October) offers many advantages that may outweigh spring planting. Transpiration is low and root generation potential is high. The temperatures are typically moderate to cool, and are easier on the plants so there is less chance for the trees to be stressed by extreme heat. The fall moisture (rains) helps the trees and shrubs establish their root systems. When the air temperatures are cooler than the soil, new root growth is encouraged without new top growth. The result is a stronger, better developed root system for the next spring when the plant begins to grow. Mulching with wood chips helps retain the soil's required moisture.

If you wait too long into the fall season (November - December) to plant, you run the risk of poor root growth and increased failure rate. Conifers, in fact, need a slightly earlier start than hardwoods, preferring the warmer soil temperatures of the summer to early fall.

Some slow to establish species are best planted in spring. These include bald cypress, American hornbeam, ginkgo, larch, magnolia, hemlock, sweetgum, tuliptree, and willow. Also broadleaved evergreens such as rhododendrons and narrow-leafed evergreens such as yews prefer spring planting. In general, plants with shallow, fibrous root systems can be planted easier in the fall than those with fewer, larger roots.

Trees that can be successfully planted in the fall include alder, ash, buckeye, catalpa, crabapple, hackberry, hawthorn, honey locust, elm, Kentucky coffee tree, linden, maple, sycamore, pines, and spruces. Most deciduous shrubs can easily be planted in fall.

Sourced form Morton Arboretum 10/08/2020

https://www.mortonarb.org/trees-plants/tree-and-plant-advice/horticulture-care/fall-planting-trees-and-shrubs

After a killing frost, remove annual plant material from your garden and add it to your compost heap.

Any soilless mix from window boxes or containers can be discarded or kept aside for one more year. If used for a second year, mix equal parts old mix with fresh soilless mix.

Clean and sterilize containers before storing over winter.

Do not mulch your perennial garden area until the ground has frozen hard later in November.

Begin to plant spring-blooming bulbs. Mulch area after planting. If rodents, deer, or rabbits have been a problem in the past, consider planting varieties of the following pest-resistant bulbs: ornamental onion, grape hyacinth, fritillary, narcissus, windflower, winter aconite.

A few weeks after a killing frost, lift and store tender bulbs. This might be as late as November. Cut back above-ground foliage and stems of cannas and dahlias to 4 to 5 inches. Gently lift up tubers using a pitchfork. Shake off excess soil and dry tubers in a warm dry place. Do not separate the mass of tuberous roots at this time. When dry, place labeled tubers in cardboard boxes lined with newspaper and filled with barely moist wood shavings, peat moss, or vermiculite. Store between 40 and 50 degrees in a darkened room. Check periodically to be sure tubers haven’t rotted (throw away) or begun to dry out (sprinkle gently with water).

Tuberous begonias can be dug in the same fashion. Remove all foliage and stems and place in a cardboard box lined with newspaper and filled with barely moist wood shavings, peat moss, or vermiculite. Store tubers in dark room between 45 and 55 degrees.

Caladium bulbs are lifted and stored like tuberous begonias.

Gladioli corms are dug, dried, and stored between 35 and 40 degrees in paper bags or open-weave mesh bags.

Tuberose planted in the garden should be dug up and have its foliage removed, then stored in a pot with very dry soil in a darkened warm room. Those planted in containers can be moved straight to storage after cutting back the darkened foliage and stems.

Harvest pumpkins before a killing frost.

Continue to harvest vegetables. If hard frost threatens, pick all tomatoes, including the unripe ones, and store in cardboard boxes or paper bags in basement.

Cut back any remaining herbs and bring them indoors to use fresh or dry.

Cover tender plants from light freezes at night by covering them with sheets, plastic, or upturned bushel baskets.

Apply a heavy mulch over leeks, Jerusalem artichokes, carrots, beets, and turnips to continue the harvest into early winter.

After a hard frost, remove all dead plant material from the vegetable garden and compost. Rototill 1 to 2 inches of organic material, composted manure, or shredded leaf mold into garden soil. Add granulated sulfur according to package directions.

Remove all fallen fruit from your garden and yard. Maintain proper sanitation throughout entire garden area.

Houseplants should be gradually acclimated to indoor conditions and brought inside before the Chicago area’s first anticipated frost of October 15. Monitor all plants carefully for insects or disease before bringing them in. Discard seriously diseased plants. Sequester new plants from those that grow indoors year-round to prevent disease or insect contamination.