Episode 1. Mid to Late September.
September 18 2025 Transcript
Informal Intro
Hey there! I am so excited you are joining me today for the first episode of my new podcast. I am Colleen Dieter, a landscape consultant at ATXGardens.com. Some of my customers told me that they wish they could get alerts or reminders from me about what to do in their yards. While I am working on other ways to send alerts, I figured maybe a podcast would be a good way to keep everyone in the loop about what is happening in our Austin and Central Texas Gardens. Today's episode is all about What to do in your garden in late September.
Sponsor note
Before we get to our gardening to do list, This episode is sponsored by my landscape consulting business ATXGardens.com. I help my customers by alleviating their anxieties about their yards. During our consultation you can ask me anything- about what to plant, how to care for your soil, tree problems, lawn maintenance, anything you can think of. You can make an appointment with me for a landscape consultation at your property at ATXGardens.com. Alright now let's get to the show!
Anecdote
This week I am organizing shopping lists for plants for my own garden and my customers. This is a great time for plant shopping and plant swapping. I offer plant shopping and delivery services as a follow-up service to customers after they hire me for consulting. I can shop wholesale so I have access to larger numbers of plants than you might be able to get yourself. Make an appointment today at ATXGardens.com
General
Do not trim your trees, shrubs or perennials now. Trimming at this time of year stimulates new growth, and we need the plants to stop actively growing in order to get ready for winter.
Mid September is the last chance to fertilize anything, including potted outdoor plants, trees, roses, lawns and perennials. Do not feed your plants with fertilizer after October 1. The fertilizer will stimulate new growth and in the winter we want the plants to stop growing.
If you don’t know what kind of fertilizer to use, don’t just buy whatever and put it on stuff. Fall is a very good time for soil testing instead. You can send a sample to Texas A&M Soil Lab, Texas Plant and Soil Lab or any soil lab in the US to find out what nutrients your soil is missing. I recommend it especially for vegetable gardens and fruit orchards.
September can be hot and damp, good conditions for plants to get fungal diseases. If your lawn, roses or other fussy plants have a history of fungal diseases September is time to sprinkle corn meal over fungal spots, spray Actinovate on the entire lawn to inoculate it with beneficial microbes. Actinovate is available in the show notes or ATXGardens.com.
Late September is time to transplant any kind of plants. At this time of year, most of the plants are reaching their maximum size. If your landscape is looking a little crowded or overgrown, when too many plants are covering each other, it is a good time to take some plants out and move them to open spaces or give them to a friend. A border spade is a great tool for transplanting available at ATXGardens.com.
Woody Plants
Mid-September kicks off planting season for woody plants like trees and shrubs. Tree and shrub planting season will continue until mid-March/April 1. Now is a good time to shop for trees because many go on sale as they start to loose their leaves and the nurseries want to make room for winter seasonal plants, pumpkins and Christmas trees etc. Even though the trees are loosing their leaves and don’t look good, dormancy, when the trees loose leaves and are not actively growing, is the best time to plant. Visit your locally-owned garden center for the best plant choices.
Some trees will start loosing their leaves in October and November. If you use a leaf blower for leaf management in fall and winter, make sure that it is working. If it is gas powered and needs to be serviced, do it now.
Webworms often get into trees this time of year. Caterpillars spin big silky pouches that protect them from predators while they dine on your trees. One or 2 pouches are nothing to worry about or intervene with. But if more than 1/3 of your tree has webworms then that is a more serious situation. There’s a few things you can do. If you can reach the webs, pull them down with gloved hands and smash the caterpillars inside. If you can reach them with pruners or a saw then cut off the infested stems. If you can’t cut them but you can reach them with something sharp, just poking a hole in the pouch can help predatory wasps enter the pouch to feed on the caterpillars.
I am the founder of Central Texas Seed Savers, and we have a program called the Seed to Tree Partnership with TreeFolks, Austin’s own tree planting organization. Fall is peak time for collecting acorns, nuts and other tree seeds to send to TreeFolks for them to start in their Seeds to Trees Native Nursery, and those seedlings are then planted throughout central Texas in reforestation programs and community tree plantings. There is a link to the Seed to Tree Partnership website with collection instructions in the show notes.
Spray your roses now with compost tea or other beneficial microbe inoculants to prevent diseases. I recommend Arber bio-fungicide, link to purchase in show notes or available at ATXGardens.com.
Sponsor Break-Middle of the Podcast commercial
Hi all, this is Colleen Dieter and you are listening to the ATXGardens Podcast. You know, I give plenty of garden advice on the show, but there’s nothing like meeting in person to get the best information for your plants and landscape. And that's what I can do for you. vsit ATXGardens.com. As a Certified Arborist and Professional Gardener, I've been giving advice to do -it -yourselfers for over 20 years. I help my customers by alleviating their anxieties about their yards. Visit ATXGardens .com to book a consultation with me. During the consultation, we'll walk through your yard together and answer all of your questions. Also at ATXGardens .com, you can shop Colleen’s favorite things, that’s gardening, apparel, tools, and books that I often mention during the podcast. From trees to vegetables to wildflowers, I'm here to help. Make an appointment at ATXGardens.com.
VIII.Perennials and bulbs
Plant perennials and ornamental grasses now. Perennials are plants that grow up in spring, bloom in summer and fall and then the tops die in winter, then they grow back again in spring. Examples include lantanas and indigo spires salvia.
September is also a great time for dividing all bulbs like Irises, Daylilies, Cannas, Amaryllis, Hippeastrums and more. I like to use a digging fork or a border spade for this job, both of those tools are linked in the show notes and available via ATXGardens.com.
Speaking of dividing, it is also a good time to divide perennials. On ATXGardens.com you can purchase my 3 volume set of booklets called ‘Let’s Care for Texas Plants’ that has a diagram and instructions about how to care for and divide bulbs and perennials.
Nature stuff
Hummingbirds should be arriving on their fall migration, so get those feeders cleaned up and expect to add more food as more come through. Remember that plants are the best way to feed hummingbirds, hummingbirds in my yard love wax mallow, common sunflowers and pokeweed.
Vegetables
Mid and late September is time to transition from hot season veg to cool season plants in your vegetable garden. Take out any summer crops that aren’t thriving anymore or that you are tired of eating like okra, black eye peas, melons, peppers and tomatoes. IF they still look good and are productive you can keep them until the first freeze, but sometimes stuff needs to go at this time of year. Use your judgement. Add some compost to the soil and then plant your cool season crops. These are vegetables that will live through the cold weather this winter. Arugula, peas, radishes mustard, turnips, bok choy, Swiss chard, beets, collards and kale can all be planted by sowing seeds directly into the garden soil. Broccoli, cauliflower, and cabbages can be planted in the garden as small plants now. You can also plant Artichokes and their cousins Cardoons as small plants.
If you are letting any part of your vegetable garden rest in the winter, plant a cover crop now. Alfalfa, rye, clovers, texas bluebonnets and Austrian winter pea are just a few of the many cool season cover crops to choose from that could be planted now.
Herbs
Plant perennial herbs now.
harvest your warm-season annual plants like basil. If your basil plants are not thriving anymore after a long hot summer, remove them to make room for cool season herbs like cilantro, parsley, dill, calendula and fennel that can all be planted in October. Be sure to add compost to your planting areas before planting anything new.
Wildflowers
This is the best time to plant wildflower seeds, especially bluebonnets, poppies and larkspurs. Here’s my recipe for wildflower success. In a wheelbarrow, trash can or on a tarp, mix together 1 bag of compost and 1 bag of granite sand. Then mix your wildflower seeds with the compost and sand. Rake the area you are seeding with a hard rake to make the soil slightly bumpy and rough. Then spread the mix of compost, sand and seeds over the top of the bumpy soil as evenly as you can. Then walk over the area to press the seeds into the soil. Then get down with your funkiest dance while you ask mother nature to bring some rain this winter. This is a good project to do with a bunch of friends, especially kids. Tune in to future episodes of this podcast for more guidance on how to care for the wildflowers as fall and winter arrives.
XIII.Conclusion:
Alright friends, that is it for this episode!
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Check out the show notes
XIV.Show Notes:
Make an appointment or shop at ATXGardens.com
Connect on Instagram @atxgardens_
‘“Let’s Care for Texas Plants” maintenance guide:
Arber Bio-Fungicide (commissions earned): https://amzn.to/47K5XdV
Collect Tree Seeds with Seed to Tree Partnership: https://www.centexseedsavers.org/seed-to-tree-partnership
Actinovate Bio-Fungicide (commissions earned): https://amzn.to/4mwznAV
Texas Plant and Soil Lab soil testing: https://www.tpslab.com/
Digging fork (commissions earned): https://amzn.to/45RnQFe
Border spade (commissions earned): https://amzn.to/4n0T3g9
