Garden Phlox, Succession Planting Veggies, My New Book and Tomato Hornworms
August is rolling in and the heat and humidity continues in our zone 5, Vermont garden. It’s made for an amazing blueberry crop year and the tomatoes are huge. We have lots of flowers enjoying this hot, wet summer and one of our late summer favorites is the tall, garden phlox. This hardy, tough perennial starts flowering now and can last into fall. There are lots of good varieties to choose from and I talk about growing them in this newsletter.
Early August is also a transition time in our garden. We’re cutting back and moving out spent early season vegetables, such as peas, lettuce and beans, and planting veggies for fall. Learn about succession planting with a few of the combinations we like to grow here.
I’ve put the almost final touches on my new gardening book, The Continuous Vegetable Garden. It won’t be available until February, 2026, but it’s already listed on Amazon so you can have a look and pre-order it if you like. Learn about what topics are in my Continuous Vegetable Garden book in this newsletter.
Speaking of vegetables, I mentioned how our tomatoes are exploding with growth and fruit. Well, it’s almost time to start looking for the beast; the tomato hornworm. These large, green caterpillars can defoliate branches of your tomatoes and even eat unripe fruit. Learn more about controlling the tomato hornworm here.
Remember to check out my monthly garden blog I write for Proven Winners called What’s Up North. The July blog features a some Perennials for the Heat. I talk about sedum, artemisia, salvia and kniphofia. These perennials thrive in full sun and hot conditions.
Until next time I’ll be seeing you, in the garden.
Charlie
Where to Find Charlie: (podcasts, TV and in-person)
- In the Garden (WCAX-TV CBS) – This week: Creating A Privacy Garden
- All Things Gardening on Vt Public Radio– This week: Currants and Gooseberries
- WJOY In The Garden Podcast– This week: Curling tomato leaves, squash growing poorly, jumping worms, hydrangea not blooming, self-sowing lettuce, deer repellents and more
- Where’s Charlie Speaking? 8/28/2025- Ecological Gardening, Burlington, VT
How to Grow: Garden Phlox
When the calendar turns to August, the tall garden phlox start to shine. We grow a number of different varieties of Phlox paniculata in our zone 5 garden. This is a great perennial plant. It’s native, attracts bees and butterflies, is tough and hardy and flowers consistently every year. Tall, garden phlox grows in a clump form and expands. Every 3 to 4 years you’ll have to divide the plant in spring, creating more phlox for your garden. It also helps keep the plant healthy.
There are many varieties of tall phlox to grow. The flower colors range from white to coral to orange to blue. Plus, there are varieties with bi-colored flowers. ‘Starfire’ is a 3 foot tall plant with bright red blossoms in late summer. It’s showy and fragrant, too. ‘Nicky’ is a similar looking variety with magenta-purple colored flowers. ‘Bright Eyes’ is an old fashioned variety with pink and red colored flowers that create a highlight in any fall garden. The one downside of tall garden phlox is its susceptibility to powdery mildew disease. This fungus really starts to spread come late summer with the cool, dewy nights and bright, dry, sunny days. Luckily, there are many mildew resistant varieties on the market now, such as ‘David’, ‘Bright Eyes’, ‘Nicky’ and ‘Jeana’ that can withstand this disease.
Plant tall garden phlox in full sun in an area with good air circulation. Avoid planting phlox next to a house, garage, wall or solid fence. This will restrict air flow creating a better environment for powdery mildew. Also, don’t crowd plants next to other perennials. For favorite varieties that don’t have good powdery mildew resistance, in spring remove all but 5 or 6 of the thickest stems per clump and top those remaining stems. This will create an airier plant that also will have more flowers. You can also spray sulfur in late summer when you first see signs of powdery mildew to stop the disease from spreading. Deadhead spent flowers to prolong the bloom season. Cut diseased plants back to the ground in fall and remove them after the flowering is finished and the leaves have yellowed.
Read more about Garden Phlox here
Succession Planting
Early August is a great time of year to rethink your vegetable garden. Many of the early veggies such as peas, radishes, lettuce and green beans, have gone by. It’s time to remove them and do some succession planting. Succession planting is a way to grow more vegetables in less space and have a continuous harvest right up to frost and beyond! It starts with being ruthless in the garden. Even if your first crop of beans has a few flowers or even small fruits left, once the main harvest is over, cut them back and remove them. If the leaves were healthy you can even chop them up and leave them as mulch. The same is true for your peas, lettuce, radish and other cool weather loving crops.
Then the fun begins. Think about fast maturing veggies, or cool loving veggies, you can plant now in all this extra space. We often plant more beans, greens, radishes, kale, Swiss chard, fava beans and fall cabbage in those spaces. These plants crop quickly in the warm soil to mature in a month or so and then hold on until or through frost. That’s what I like about a fall veggie garden. If you can grow your seedlings well through August, the shorter days in September and October will slow the plant’s growth so you’ll have plenty of time to harvest when you want.
Some succession planting we do include, following peas and lettuce with beans, collards and Swiss chard. Following the first crop of beans with kale. Following onions and garlic with fava beans, beets, radish and lettuce. And following bush beans with quick maturing varieties of summer squash.
There are some considerations with planting this time of year. The soil is very warm. In fact sometimes too warm for seeds to germinate. So, often the best method is to purchase or start seedlings indoors to move outdoors. This will help them get off to a good start. Also, the seedlings are more likely to survive pest attacks. We also cover these new beds with micromesh row covers to keeps pests away, keeps the soil more evenly moist and protects them from thunderstorms. Keeping the soil evenly moist is important especially for germinating carrots, beets and lettuce. It also keeps the soil cool, which they like. So, with a little planning, you could be harvesting as many veggies in fall, as you do all summer.
Learn more about Succession Planting here
My NEW BOOK: The Continuous Vegetable Garden
I know. My new book, The Continuous Vegetable Garden is seven months away from being released, but at least give me credit for being excited! I’ve been working on this book for one year and it’s nice to see it come together. What I love about this book is it pulls together many techniques, concepts and ideas that we’ve been doing for years in our garden. Many of these ideas, such as succession planting, interplanting, growing perennials vegetables, growing self sowing vegetables and saving seeds, are not new of many gardeners. But I’d like to think that the Continuous Vegetable Garden book brings them all together in the plan that is approachable and easy to follow.
Those of you who have purchased some of my other garden books, such as the Complete Guide to No Dig Gardening, will recognize some of the content. But, I purposely don’t dwell on common vegetable gardening techniques and methods but really spend time in the bulk of the book pulling together various ways you can garden in less space and easier all while producing a constant flow of food from your garden all growing season. That’s the premise of my book.
While the main focus is vegetables, I also include information on perennial herbs, self sowing edible flowers and a whole chapter on dwarf fruit. In fact, I lay out how to have fresh fruit from your garden from May to November in a zone 5 garden. There’s information on season extending, protecting plants from the weather and pests and even indoor growing of edibles. There’s even fun sections on overwintering your favorite tomato plant indoors in a dormant state and getting your artichoke plant to overwinter as well. To cap off the book, we had an artist illustrate a number of garden designs I use showing how all the techniques come together. You can take the book and start planting next spring. So, check out the Continuous Vegetable Garden book on line. You can preorder it now or just wait until February when it will be out.
Learn More about the Continuous Vegetable Garden Book here
In Our Garden: Pest of the Month: Tomato Hornworm
If you grow tomatoes, sooner or later you’ll run into the tomato hornworm. This large caterpillar is the larvae of the sphinx moth. This night flying moth lays eggs on tomato leaves in mid summer. The eggs hatch into green caterpillars that eat and eat and eat until they grow to 6-inch long mammoths! The irony is although this is a large insect causing lots of damage to leaves and fruits, they often are hard to see. Their color blends in with tomato leaves, so they often go unnoticed.
If you see damage on your top leaves and fruits, then it’s time to check for the tomato hornworm. Looks for dark green droppings on the leaves. This is the hornworm’s poop. If you look straight up from there, you’ll probably see the hornworm. You can also take a black light into the garden at night and the hornworms will glow. Pick off the individual hornworms and drop them in a pail of soapy water or feed them to chickens. If you have a lot of hornworms spray Bt organic spray on the tomatoes, being careful not to let the spray drift to other plants. Bt will kill hornworms, but also other butterfly larvae such as swallowtail butterflies.
Another trick for next year is to interplant basil with your tomatoes. Research has shown that 4 or 5 ‘Genovese’ basil plants around each tomato will confuse the moth. The scent of the basil masks the scent of the tomatoes so the moth flies right over your tomato plants without laying an egg. If you happen to see white protrusions on the back of your hornworm, leave them. These are the cocoons of the braconid wasp. It’s a parasitic wasp that will kill the hornworm once they hatch and infect more hornworms.
Go here for more on Tomato Hornworms
