Planting Peonies, Spotted Lanternflies, Pokeweed, and Other September News | Home Garden Education Office | College of Agriculture, Health and Natural Resources

Peonies

This month is the perfect time to plant, divide, or transplant peonies, allowing tubers to establish themselves before winter arrives and the ground freezes. Six weeks of temperatures below 40°F are required for proper flowering in the spring. Choose a site with full sun and well-drained soil to avoid root rot issues. Dig a hole large enough to fit the tuber and its root system, working a form of organic matter, such as compost, into the soil. Nestle the tuber inside—about 1-2 inches from the soil surface. Planting too deeply will prevent proper flowering in the spring. Water the new planting well, adding mulch if needed to maintain moisture.

If transplanting, cut peony stems close to ground level. Dig around and under the plant to gather up the root system. Similar to when planting new tubers, transplanted peonies should not be buried deeper than 2 inches below the soil surface.

If dividing a previous planting, carefully dig up the peony and its root system. With a properly sanitized tool, carefully cut the root tubers into small sections with 3-5 buds each and plant according to the guidelines above.

About Peonies

Peony Care

Spotted Lanternfly (Lycorma delicatula)

Spotted Lantenrfly (SLF) is an invasive insect introduced from Asia. It arrived in Connecticut in 2020 and has since spread throughout the state. The preferred host plant is Tree of Heaven (Ailanthus altissima), but it will feed on many other genera of plants. SLF poses a threat to Connecticut agriculture because of its feeding on some fruit crops. At this point in the season, destroying eggs by scraping or crushing them will be most effective at reducing next year's population. Nymphs and adults can be treated with contact insecticides including insecticidal soaps, horticultural oils, or other insecticides according to label instructions. Circle traps can be used to capture nymphs next year.

About Spotted Lanternfly

About Tree-of-Heaven

How to Build a Spotted Lanternfly Circle Trap

What to Know about Spotted Lanternfly in Connecticut

Tree of Heaven (Ailanthus altissima)

Tree of Heaven (TOH) is an invasive tree in CT. It is also the preferred host plant for the invasive spotted lanternfly (SLF). This tree forms dense colonies through its suckering root system. Female trees can produce hundreds of thousands of seeds annually. Removing this tree is recommended, but careful consideration should be taken because when injured or cut down, the tree can produce many stump sprouts or root suckers. Systemic herbicides applications are recommended from mid-summer through early fall.

Pokeweed is a native perennial that is having a banner year in 2026 in Connecticut. With its multiple branching habit and height-up to 10 feet- it can be mistaken for a shrub.

It is generally considered a weed in gardens and residential spaces. However, in the wild, the dark purple fruit are of value to birds and small mammals.

Pokeweed is best controlled is by pulling out young plants before the taproot gets firmly established. Other control methods are highlighted in the article below.

All plant parts are poisonous to humans and pets, and wearing gloves, long sleeves and closed toed shoes is recommended when handling all parts of the plant.

Learn More About Pokeweed

Controlling Pokeweed

Interesting Insects: American Lady Butterflies

Orange and brown butterfly with black and white markings resting on a green leaf. — Photo by Pamm Cooper, UConn Home Garden Education Office

American lady butterflies, Vanessa virginiensis, are among the several butterfly genera that migrate in both spring and fall, like the monarchs. As they head south in late summer, flowers like goldenrods, Tithonia spp. of Mexican sunflowers, zinnias, asters and lantana are among the plants they use as food sources on their way south.

This is a very fast flyer as it wings its way around the landscape. It is very similar to the painted lady, Vanessa carduii, but it has two large eyespots on the rear wing instead of the four smaller eyespots of the painted lady. Plus, the forewing orange cell of the American lady just below the dark area with the white markings has a white dot in the center.

American Lady vs. Painted Lady Butterflies

Beaked Hazelnut (Corylus cornuta)

Corylus cornuta, is a native, easy to grow multi-stemmed shrub that grows in full sun to part shade. It can form thickets by sending up suckers from rhizomes.

Edible nuts about a half inch in size are enclosed in a beaked husk, and nuts can be harvested in late summer. The fruit is unique when joined together in pairs- the whole fruit resembles Brunhilda 's horned opera hat. Fall leaf color is yellow bronze.

Learn More About Beaked Hazelnut

The CT Native Plant Availability List: Updated and even MORE user-friendly!

This native plant guide was created to assist municipalities, conservation organizations, homeowners, landscape architects, designers, and contractors with locating native plants for habitat restoration and wildlife enhancement.

The Connecticut Native Plant Availability List, by UConn Extension and CT DEEP Wildlife Division, identifies nurseries and garden centers that grow/sell native trees, shrubs, and perennials. Along with several nurseries that are new to the list, we have also added the ability for users to view the Availability List sorted by Nursery!

CT Native Perennial, Tree & Shrub Availability List

Word from the WiSE

Women in Soil Ecology, UConn Student Chapter

Get The Dirt On Your Soil - Soil Test This Fall!

As the summer season comes to a close and fall starts to move in, the perfect time to test your soil rapidly approaches. A fall soil test can help you start preparing for the following spring and summer season, even before winter begins! A soil test allows you to get a glimpse of what is going on in your soil, like the pH, nutrient levels, organic matter, and more! It helps to establish a base line to see if any soil amendments need to be added to improve your soil health. If any are needed, applying slow release nutrients, such as lime, in the fall can be very beneficial as the additions can slowly release into the soil over winter, and have your soil ready for growing in the spring. Fall crops and ground cover can even uptake the nutrients and have an even better spring green up! Don’t guess, soil test this fall!

By Zaira O'Leary, Soil Science Master's Student, UConn PSLA

Fall is the Perfect Time for Soil Sampling

Fall is a Great Time to Lime and Fertilize Lawns

UConn Soil Nutrient Analysis Lab

George Leigh Minor Plant and Soil Health Center Open House

October 17th, 2026
11:00AM - 3:00PM
27A Manter Rd, Storrs CT

Join us for a free, family-friendly open house at UConn’s newest center! Learn more about our services and expertise in home gardening, plant diagnostics, soil and nutrient health, and turfgrass.

- Tours of the new George Leigh Minor Plant and Soil Health Center

- Hands-on plant and soil health demonstrations

- Lawn and garden questions answered

- Free soil pH testing

- Free plant diagnostic/nutrient analysis coupons (limited qty)

- UConn Hort-club Plant sale

- UConn Dairy Bar will be open

- Wagon rides, games, prizes, and more!

UConn Master Composter Program

What is the Master Composter Program?
Between 10 and 25% of a typical household’s waste can be recycled right in our own backyards. This significantly reduces the amount of waste that is incinerated or trucked to state and municipal landfills. The UConn Master Composter Program educates and trains state residents about the composting process and prepares participants to pass that knowledge on to others through outreach.

Program Details
Format: Hybrid, with two in-person Saturday sessions and two online evening sessions

Program fee: $100 per student

Class size: Limited to 25 participants

Certification: Participants must attend all class sessions and complete outreach projects totaling about 20 volunteer hours to receive a UConn Master Composter Certificate & Badge.

Suggested topics: Composting basics; compost chemistry, contaminants, and testing; compost recipes and calculators; community composting; earthworms; vermicomposting; and public education approaches.

For more information including registration and program updates, email soiltest@uconn.edu.

2026 CIPWG Symposium

The Connecticut Invasive Plant Working Group's 2026 symposium From Awareness to Action - Strengthening Our Response to Invasive Plants will be in person at UConn Student Union, Storrs, CT, open to all; Wednesday, October 28, 2026.

Sessions include a variety of techniques for management of terrestrial and aquatic invasives, as well as restoration with native alternatives.

The symposium will be recorded and made available after the event. Attendees can choose to attend in person or purchase the recording. CEUs for organizations and Pesticide Recertification Credits are available.

$90 General Registration (in person attendance). $80 Recording Only; Student Registration Available.

Learn more and register at: cipwg.uconn.edu/2026-symposium/

Ornamental & Turf Short Course Fall 2026

Registration is now open for the Fall 2026 Online Ornamental & Turf Short Course! The course runs October 7–December 16, 2026, with weekly live online sessions held on Wednesdays from 5:30–7:30 p.m.

Registration Cost: $400 (includes the Pesticide Applicator Core Manual, Ornamental & Turf Category Manual, and printed course materials).
For information on student registration or if you are retaking the course, please contact the instructor, Srikanth Kodati (contact information can be found at the end of this email).

This short course provides an in-depth review of the material needed to prepare for the Connecticut Supervisory Pesticide Applicator Certification Exam (Category 3A: Ornamental & Turf/Golf Course Superintendents). Students who complete all modules, quizzes, and resource materials will be well prepared for both the written and oral state exams.

To register for the course:
s.uconn.edu/turfcourse

For more information: https://ipm.cahnr.uconn.edu/pesticide-course/

Please reach out to Srikanth (course instructor) at srikanth.kodati@uconn.edu or call 860-870-6935 if you have any questions.

September Gardening Tips

Mid to late September is a great time to add accent plants, like vivid mums and starry asters, that will provide autumn colors in the landscape. Use them along with cool-colored ornamental cabbages and kales to replace bedraggled annuals in containers as well

Lift and store tender bulbs, such as cannas, dahlias and gladiolus, after first frost

Spring and summer blooming perennials like daylilies and bearded irises can still be dug up and divided

Early autumn is a great time to plant perennials

Do not fertilize perennials any more this season. Pushing new growth too close to frost can cause damage to your plants

Late season cabbage and beets can stay in the garden until a light frost for best flavor. Some root crops, including certain varieties of beets, carrots and parsnips, may be left in the ground for storage. Wait until temperatures drop and growth stops and cover with a thick layer of straw or leaves. Harvest as needed during the winter. This may not be an option in areas with heavy vole populations.

Continue to water any new shrub or tree plantings until the first hard frost.

Continue to turn and moisten compost piles to speed decomposition.

Apply fall fertilizer to lawns between Sept. 15th and Oct. 15th.

As tomatoes end their production, cut down plants, pick up any debris and put dead/diseased plant parts in the trash or take to a landfill. Many diseases will over-winter on old infected leaves and stems so these are best removed from the property.

Harvest onions once tops have fallen over and necks have started to dry down and shrink just above the bulb.

More September Gardening Tips

O sweet September rain!
I hear it fall upon the garden beds,
Freshening the blossoms which begin to wane...

Peonies