Summer of 2022 marched in like a lion yesterday, and the forecast reads hot, hot, hot as far the eye can see. While the greater Durham area isn’t currently experiencing drought, NOAA’s National Integrated Drought Information System (https://www.drought.gov/states/north-carolina) currently shows large areas of North Carolina experiencing extreme dryness, moderate drought, and even some severe drought. Of course, scorching temps and lack of rain have major implications for your garden and landscape. These tough conditions make EMGV Andrea Laine’s 2018 article below on watering a must for your summer reading list!
The good news is there are currently no drought advisories in North Carolina. The southeast received an average of 7.05 inches of precipitation in May, way above normal. So, we entered June strong. But with the heat index pushing temperatures way past 90°F this week, gardeners do need to be mindful about watering.
Here are helpful reminders:
During periods of extremely hot weather, a plant can lose water through transpiration faster than its roots can take water from the soil, which is why we see wilting on hot days even when we’ve had ample rainfall. Learn more about the hows and whys of wilting. https://durhammastergardeners.com/2016/08/25/why-plants-wilt/
With Japanese Beetles showing up everywhere from ornamentals to fruit trees, now is the perfect time to revisit this great post by Kathryn Hamilton. Stay out of the heat for a while and learn what you can do to protect your plants – your roses will thank you!
At this time of year, Japanese Beetle “Season,” my favorite gardening tool is a plastic fork. When disrupted, beetles are supposed to fold their hind legs and fall. You are supposed to be able catch them with a container of soapy water. In my experience that’s true only about half the time. Sometimes they must be pointed in the right direction; other times they need to be fished out from between the layers of a rose petal, and at still other times, they must literally be pried off the flower. Apparently, even Japanese beetles have a survival instinct!
Japanese beetles (Popilla japonica) are attracted to the foliage, fruits, and flowers of nearly 300 different plants, among them: roses, crape myrtle, hibiscus, purple-leafed plums, grape leaves, and geraniums. If you are a Piedmont gardener, chances are very good that you have encountered these pests in recent weeks.
The good news is that Japanese beetles are unlikely to destroy established trees or shrubs. Skeletonized leaves and flowers will grow back once the beetles disappear. The better news is that within 30 – 45 days of their onset they will be gone.
Here are some takeaways to help you cope with Japanese Beetle “Season.” 1. Only one generation occurs each year. They typically emerge in early June and are gone by mid-July. You may see an isolated beetle during the rest of the year but ground zero is late May until early July.
2. Beetles emerge when the temperature is “just right.” Scientifically this equates to approximately 1,000 growing degree days. (Here’s a scientific explanation of growing degree days.) If the weather heats up faster beetles are likely to appear sooner. Weather conditions also determine the grub population, their larval stage. Damper weather typically means more grubs. More grubs mean more beetles.
3. Japanese beetle traps should not be considered control devices. Designed to attract beetles, rather than trap them, they can increase the beetle population in your back yard. Furthermore, if not emptied every couple of days, the beetles will rot inside, releasing an ammonia which repels them. Instead of going into the trap, they are likely to tap your hibiscus.
4. Japanese beetles aggregate in response to odor released by damaged plants and a pheromone released by female beetles. I usually cut the least-damaged roses and leave one or two that have been attacked. They are always one of my best beetle-harvest sites.
5. Where practical, cover the plant with light netting.
6. Just say “no” to things they don’t like. But who could imagine a garden without roses?
7. Rose experts advise picking your roses and bringing them inside. They can beautify your property the rest of the year.
8. Another tip, before cutting a rose to bring inside, be sure the sepals have fallen or the rose will not bloom.
9. You can, of course use insecticides, a discussion of which is outside of this posting. However, any insecticide will have some negative effect on other insects, including those which are beneficial. The North Carolina Agricultural Chemicals Manual lists pesticides and their relative safety for bees. Should you opt for an insecticide, prune all the flowers first. There are label restrictions against using most insecticides on flowering plants and when pollinators are present. Read the label for detailed restrictions.
10. Insecticides only treat the exposed petals. So, if a bud opens throughout the day, the unprotected petals are just another meal. And, unless they are systemic, insecticides must be reapplied after a rain.
My bottom line strategy: I cut my best roses and leave a few that have already been attacked as traps. Several times a day, I am single-mindedly devoted to search and destroy missions, first dumping the beetles into a container of water soapy water then finishing with a flush down the toilet.
Merely mentioning the word mint to gardeners may send them running in the opposite direction for fear of being overtaken right where they stand by this pungent, intoxicating herb. While plants in the Mentha genus such as spearmint (Mentha spicata) and peppermint (Mentha x piperita) may invoke pleasant memories of chewing leaves on lazy afternoons in your grandmother’s garden and definitely have an honored place in the culinary world, their invasive growth habits can show little respect for boundaries and quickly become problematic in the garden.
Well…how about mountain mints? I really only became aware of these plants within the last few years. With the interest in pollinator-friendly gardening on the rise, I began hearing horticultural experts sing mountain mints’ (Pycnanthemum spp.) praises as one of their top picks for the landscape.
Mountain mints are native to the Eastern US and grow in all areas of North Carolina. In their naturally occurring habitats, you’ll often find them growing in moist open fields, at the edges of forests, and in lower elevations despite the alpine-sounding name. Both culinary mints we know and mountain mints are in the same scientific family (Lamiaceae), but they are different genera —Mentha and Pycnanthemum, respectively. However, both share a minty or thyme-like fragrance when crushed. Aside from smelling great, these plants have a lot going for them. Mountain mints are known for their rabbit and deer-resistant properties. Mountain mints are also super pollinator attractors, with their nectar drawing a host of beneficial insects. From June until September, look for scores of native bees, honey bees, wasps, moths, and butterflies buzzing around this plant. In a 2013 Penn State Extension study testing 86 native species and cultivars, clustered mountain mint attracted the most diverse group of pollinators of all the plants tested. (1)
Most mountain mints have bracts much like our beloved North Carolina state flower the Dogwood blossom (Cornus florida), some silver in appearance. The plant’s small flowers range from white to light pink to lavender in the compact center of the plant (called a cyme) and give a subtle ornamental effect. A few as outlined below can offer more showy flowers. These perennial and deciduous plants have a mounding upright habit and generally reach a mature size of 3 feet tall by 3 feet wide. And let me tell you, this plant is versatile. Mountain mint is excellent for naturalizing a larger area, in a cottage garden, for native plant gardens, or even mixed in a perennial border or bed. And while it flowers best in full sun, it can also grow in part sun to part shade. It’s typically not picky about soil either; it only wants good drainage. Its dense growing habit means it can serve as a great weed suppressor. Mountain mints can be grown by either seeds or plant division. While not as invasive as true mints, it can spread out over time at a typical rate of 4-6 inches annually. Keeping it in check is fairly easy, though. If the plant gets too big, dividing or simply severing part of the plant’s rhizome root system with a spade is enough to rein it in each year.
Detail of silvery bracts surrounding compact clusters known as cymes with delicate lavender flowers. (Image Credit: Cathy Dewitt CC BY 4.0)
While there are over 20 species of Pycnanthemum and many can be found in North Carolina, here are a few examples to whet your appetite for this pollinator-friendly plant. The following mountain mints can often be found for sale these days at local nurseries, especially those that have a focus on native plants.
Narrow-leafed Mountain Mint (P. tenuifolium) and close up of its flowers. The North Carolina Botanical Garden crowned this species its 2019 Wildflower of the Year. The needle-like leaves lend great texture and the clustered white flowers are a stand-out addition to the garden. (Image Credits: (Left) Cyndy Sims Parr CC-BY-SA 2.0; (Right) Dan MullenCC BY-NC-ND 2.0)
Hoary Mountain Mint (P. incanum) leaves, bracts, and flowers. This species gets its name from short white hairs that cover its stems. It has a lovely silver appearance that makes you think the plant could have been lightly dusted with snow or powdered sugar on both leaves and bracts. The wider leaves are a good identification guide. (Image Credits: (Left) S.B. JohnnyCC BY-SA 3.0); (Right) Tom PotterfieldCC BY-NC-SA 2.0)
Appalachian Mountain Mint (P. flexuosum) with its impressive architectural blooms and the distinct leaves. This type of mountain mint is found most frequently in the Piedmont to the coast in North Carolina. It sports more flowers than other Pycnanthemum species that are white to lavender in color and can be used for cut flowers. These impressive blooms turn into lovely dried seed heads if left to overwinter in the garden. This species is a larval host plant for the Gray Hairstreak Butterfly (Strymon melinus) and supports the wavy-lined Emerald moth (Synchlora aerata). (Image Credits: (Left) Debbie Roos; (Right) Leaves, Nate HartleyCC BY-NC 4.0).
Blunt Mountain Mint (P. muticum) is also known as short-toothed mountain mint. This species is often less drought tolerant than other Pycnanthemum and prefers moist to medium well-drained soils. It also supports wavy-lined Emerald moth larva, and its native habitat is often woodland areas and thickets. Its dark green leaves can also appear sugar-coated when planted en masse. (Image Credits: (Right) Fritz Flohr ReynoldsCC BY-SA 4.0; (Left) Flower and Bee (Wake County, NC)Cathy DewittCC BY 4.0)
Make room in your garden for mountain mints! They are plants worth discovering.
(1) Ellis, K. 2013. Identifying and Promoting Pollinator-Rewarding Herbaceous Perennial Plant Species. Final Report to Pennsylvania Department of Agriculture. 16pp.
Will you look at that! It’s June…already. Did May actually occur? Oh, yeah. Now I remember. There was Mother’s Day, and a grandkid graduated from Duke and Memorial Day (really short memory here), and planting, watering, mowing, affordable housing meetings… Sheesh! No wonder I lost track. The plate overfloweth. But wait. June has white space on its calendar. Whoa. What’s that all about? I’ll take it. The gardening calendar, however, is not resplendent with white space. First, though an update on the Accidental Cottage Garden.
The Accidental Cottage Garden is popping with color thanks to (Left) the Asiatic lily (Lilium x ‘Corsica’), (Top Right) butterfly weed with a bumble bee friend (Asclepesis tuberosa), (Bottom Right) gallardia (G. puclchella), and the Mexican hat (Ratibida columnifera). (Image Credit: Gary Crispell)
The space in front of the house is spectacular. The Siberian Wallflower (Cheiranthus allionii) that Melinda ID’d for me (Thank you, Melinda!) is nearly done as is the dianthus (Dianthus x ‘Sweetie Pie’). The new orange is butterfly weed (Asclepesis tuberosa) and the new pink is an Asiatic lily (Lilium x ‘Corsica’). They have lots of friends blooming or fixin’ to. The English daisies (Bellis perennis) contrast nicely with the gallardia (G. puclchella), the Mexican hat (Ratibida columnifera), and the Knockout rose (Rosa x ‘Radtko’). Because it no longer fit in the backyard plan there is a potted hibiscus (Hibiscus x hybrid) in front of the kitchen window. There are two plants in the pot, a double red and a double orange. We love it because when everyone else is hot and tired she just keeps blooming (as long as I remember to feed her regularly).
Now let’s get at that gardening calendar before July runs us inside to the AC.
Last call to get off your duff and feed that warm season grass (Bermuda, zoysia). Well, maybe not THE last call, but if you really want a lush green lawn all summer…just sayin’. Of course, we know you sent in a FREE SOIL TEST last fall or this spring so you know exactly how much and what N-P-K ratio to apply, right? (They are free from April through November, friends.) Click HERE for more info on soil testing.
June is THE month to fertilize centipede grass. If you, too, didn’t get a soil test, the recommended application is ½ pound of 15-0-14 or equivalent per 1000 square feet.
June is as good a month as any (and better than most) to core aerate any lawn. It will facilitate getting water and nutrients down in the root zone where the plants can use them. And it puts air into our heavy Piedmont soil. Win, win, win.
Keep warm season lawns mowed to a height of 1 ½ inches and cool season lawns to 3-4 inches.
This is a great time to fertilize dogwoods (Cornus spp.).
Vegetable gardens will reward you later if you side dress them now with a little balanced fertilizer.
For everybody who has been trying to out-wait the frost; it’s gone until October and you can plant the veggie garden now. It is a bit late for seeding most things, so transplants are in order for these guys: tomatoes, peppers, black-eyed peas, lima, green and wax beans, pumpkins, sweet potatoes, squash, cucumbers, etc.
Start from seeds for mid-July planting Brussels sprouts, broccoli and collards.
June is a fine time to prune lots of stuff. Make sure the pruning tools are sharp and lubricated (Not the operator, though. Only the tools should be lubricated.)
Coniferous (seeds form in cones) evergreens such as cedars, arborvitaes, chamaecyparis, junipers, cryptomeria, pines, etc. fall into that category and may be pruned now. Not severely, though. They don’t generally put out new growth below the cut.
Azaleas should be pruned before the 4th of July except for Encores® which to my limited knowledge, need only be pruned for shape and usually in the spring.
Sometimes acid-loving plants (ericaceous plants) suffer from a disease called dieback. Prune it out as soon as you detect it by making cuts 4-6 inches below the affected part and sanitize the pruner with 10% bleach between cuts.
Hydrangea macrophylla (macro=big, phylla=leaf) can be pruned when the flowers fade.
Keep garden mums (Chrysanthemum spp.) pinched back until mid-July for fall blooms.
PEST CONTROL AND HERBICIDES
Be vigilant in looking for June’s usual suspects—lace bugs, leaf miners, aphids and bagworms. If the bagworms have already ensconced themselves in bags you will have to pick them off the plant and dispose of them as you see fit. (I smush ‘em.) Treat the others as necessary with an appropriate insecticide. As always read the label and follow the instructions.
Be aware of tomato early blight. It is caused by either of two closely related fungi, Alternaria tomatophila or A. solani. (Sometimes I actually research this stuff.) The initial symptoms are dark spots on the leaves. The spots will eventually form concentric circles, yellow and then brown the leaves. Remove infected leaves and treat the plant with fungicide. There are organic options.
While we’re in the veggie garden (If one grows tomatoes in the flower garden, is it a flower garden with tomatoes or a tomato garden with flowers? Isn’t philosophy fun?) There are hordes of insects in there that think every week is “Restaurant Week” for them. Look out for any number of different worms on cruciferous vegetables (cabbage, broccoli, etc.), cucumber beetles on cucumbers and melons, squash vine borers on other cucurbits (squash, melons, etc.), flea beetles on green beans, tomatoes & eggplant and aphids on just about everything.
(Left) Scout your garden frequently in June for early blight on tomatoes. Note the concentric circles on the leaves of this infected plant. (Image credit: Inga Meadows) (Center, Right) Another pest to watch for is the cucumber beetle who loves your cucumbers, squash, melons. It can come to your garden party dressed in spots or stripes. (Image credits: Debbie Roos and UNH Extension/ Alan T. Eaton)
Japanese beetles will make their grand entrance sometime this month. Spray them, powder the plants or pick them off and drown them. (My dad gave me a penny a beetle back in the Cretaceous Period.).
Poison ivy/oak, kudzu and honeysuckle are ripe for eradication (or at least a modicum of control) this month.
As usual, continue spray programs for roses, fruit trees and bunch grapes.
OTHER ASSORTED GARDEN RELATED OUTDOOR ACTIVITIES
You know at some point this summer it will be necessary to supplement Mother Nature as her summertime efforts tend to be sporadic and frequently insufficient. Plants (lawns and gardens) need about 1 inch of water per week to remain healthy. Irrigation water is best applied in the morning to minimize evaporation and the spread of disease. (Mother N knows this, but does not read this blog.)
Strawberry beds can be renovated now because strawberry fields are not forever, actually.
Patios and decks should receive maximum use this month. Cool beverages, lite hors-d’oeuvres and good conversation with friends are recommended. Organic varieties of each are available.
Happy summer, y’all. Enjoy this, the “goodliest state”.
By Ashley Troth, PhD, Durham County Extension Agent, Agriculture-Consumer and Commercial Ornamental Horticulture
They may look small and sweet now, but don’t let your tomato plants fool you. Without proper support, tomatoes are sprawling vines that can often have problems with disease, leading to poor fruit set. By planning ahead and selecting the right supports for your type of tomato, you can keep plants off the ground, increase air flow around leaves, and give your plants a fighting chance against many southeastern tomato diseases.
Tomatoes come in two major varieties: determinate and indeterminate. Determinate tomatoes set fruit over a short period and are typically smaller plants overall. Many dwarf tomato varieties are determinate. Indeterminate tomatoes grow and set fruit throughout the season, leading to large plants that can reach 10+ feet tall. Many cherry and grape tomatoes are indeterminate, as well as many heirloom tomatoes.
While many dwarf tomato varieties require little support and can get by with tomato cages, for larger determinate and indeterminate varieties, it’s worth doing some extra work upfront to set your tomatoes up right.
One good option for supporting smaller determinate tomatoes is the Florida weave (also call “basket weave”) system, which uses fewer stakes than individually staking plants. This system can be used for indeterminate varieties as well, but they will need to be trimmed once they reach the top of the stakes and are overall more likely to be too heavy at maturity for this support system.
To begin, place 5 to 6 feet sturdy wooden or metal stakes every two to three plants at transplant, with double stakes at the end of each row for strength. Stakes should be set at least 6 inches deep, although consider setting stakes up for a foot deep for extra support. For indeterminate varieties, taller stakes will provide better support.
Once stakes are set, weave twine in a figure eight pattern between tomato plants, wrapping twice around each stake down the row. At the end of each row, begin weaving back down the same row in the opposite direction, gently sandwiching young plants between twine rows. The first row of twine support should be placed 6 to 12 inches above the soil and can help plants from leaning and allowing leaves to contact the soil. As plants grow, weave another layer of twine every 6 to 8 inches to keep plants well supported.
Larger indeterminate varieties of tomatoes truly are vines that will just keep growing given the right conditions. These large plants will benefit from heavy trellises or cages. Large cages can be built from wood, rolled wire fence, or agricultural fence panels. Examples abound online, but keep in mind that whatever material you choose, you will need to be able to easily reach around the plant to collect fruit, prune, and scout for pests. Openings in the trellis or cage that are at least 4 inches square are recommended. Secure plants to trellises with soft materials such as jute twine or bits of old stockings or t-shirts to prevent ties from cutting into the plants. Always tie plants gently, with a bit of give where they are secured.
Another option for larger plants is to provide overhead support. In this system, tall posts (8 feet or taller is preferred) are anchored on either end of tomato rows, with heavy wire run between the posts. A length of twine is hung from the wire for each individual plant, and plants are secured to the twine as they grow using specialty tomato clips. Prune plants to keep only the central vine (remove suckers/off-shoots), and clip every 12 to 18 inches to secure. Removing suckers will cause plants to produce fewer fruit, but fruit will be larger overall.
Want to learn more about growing your dream tomatoes? Check out the excellent resources below.
Resources and Additional Information
The University of Maine has put out a great video series on multiple approaches to support tomatoes. Check out all three short videos to see what’s best for your plants!