It's Time to Get Intimate With Your Garden
It is mid-July, and my morning routine looks like this: I walk out the patio door, coffee in hand, and stick a finger down into the soil of the nearest pot.
We’ve had rain on and off and then heat, and the container is already sucked dry. Summer in Minnesota does not wait for anyone.
This is the season when gardens shift from promise to performance. It is also the season when trouble sneaks in. Heat, humidity, heavy rain, hungry rabbits. So for this installment of my ongoing conversation series with Laura Irish-Hanson, horticulture educator with University of Minnesota Extension, I asked her: if you could walk through every Minnesota garden right now, what would you have us check first?
Her answer surprised me a little, and then it made perfect sense.
First, Get Close. Really Close
“Look for insect and disease pressure,” Laura told me. “Go and not just look at the plant from afar. Go get intimate, get close to them. Look on the top of the leaves, flip the leaves over, get on your hands and knees and look underneath.”
Laura says insects like to hide where stems and branches meet, or in that little crook where a leaf joins the stem. And here is the spot most of us never think to check, especially container gardeners: under the pot itself. This was new to me. Some insects hang out on the bottoms, lips, and edges of pots, and they can persist from one year to the next, carrying insect pressure into a brand-new season.
One caution before you go on the attack: not everything you find is an enemy. “We don’t want to kill everything we see,” Laura said. “Some insects are beneficial. Some of them are native insects.” Identify before you act, and be picky about your sources. Laura says do not trust the first thing your search engine serves up. Extension websites pair reliable identification help with sound management strategies.
What Extension Is Seeing Right Now
With this run of heavy rain, humidity, and heat, I asked Laura what is showing up across the state. Powdery mildew, of course, which appears nearly every year and all season long, with Monarda among the usual suspects. Educators in northern Minnesota are reporting more tree disease issues, a lingering consequence of years of drought and winter stress. Environmentally stressed plants are simply more vulnerable to bad disease outbreaks.
On the critter front, rabbit and squirrel complaints top the list, which is business as usual. Central Minnesota had a big year for sawfly damage, with some plants completely defoliated a few weeks back. Viburnum leaf beetle also hit hard, stripping viburnums growing in shade to part shade and killing off many shrubs. Japanese beetles, mercifully, have been scarce so far this season.
When Rust Came to My Patio
I told Laura about my own hard lesson this summer. My four containers of Karl Foerster feather reed grass developed grass rust, and by the time I realized it, 60 to 70 percent of the plants were infected. I had assumed container grasses were impervious to this sort of thing, and that they could not catch it from grasses nearby. Wrong on both counts. Four feet around the corner, established in-ground Karl Foersters were carrying rust too, with just enough spores to float over to mine.
“A lot of plant diseases actually stick in plant families,” Laura explained, “and our grasses all come from the same plant family.” Some diseases are hyper specific, affecting only one or two species. Some are even cultivar specific. Karl Foerster is a cultivar, planted extensively precisely because it is generally disease free. But this year’s warm temperatures and high humidity have given fungal diseases a boom season.
The reassuring news: rust usually will not kill an established ornamental grass. For most gardeners it is an aesthetic issue. But container-grown grasses are a different story. “Those can take a lot of watering,” Laura noted. If watering is not consistent, potted grasses get stressed. And stressed plants get sicker.
Tomato Trouble, Basil Blues
My patio tomato has been a champion this year, a great crop for a little container. But several leaves have developed pinpoint holes, like needle incisions. Laura walked me through the possibilities.
Many tomato diseases, it turns out, are transferred on cages and pots that were never sanitized between growing seasons. Her fix: one part bleach to nine parts water before reuse. The tiny spots could point toward blight, though she did not think it sounded like septoria leaf spot. And here is a fact that made me pause: septoria spores can lie dormant in soil for over 20 years, just waiting for rain or careless watering to splash soil up onto the leaves.
That soil splash is the engine behind many tomato diseases, which is why Laura’s advice is to prune out affected leaves as soon as you see them. Then dispose of them properly. “Don’t just drop them on the ground,” she said. Send diseased plant material to a commercial compost facility that accepts it, not your home compost, which almost never gets hot enough to kill pathogens. No facility nearby? Seal the material in a plastic bag, leave it in the sun for several weeks until it has thoroughly cooked, and then it can be composted safely.
Of course, my pinpricks might not be a disease at all. An insect with a piercing, sucking mouthpart leaves similar calling cards. So I did what Laura preaches: I flipped the leaves and looked. No insects in sight, but as she reminded me, early detection is the whole point. “Getting intimate with plants is always the best thing we can do.”
So for now, my tomato mystery remains an open case. I did spot some little black beetles a month or so back, but they got away without a photo, so I can’t confirm the culprit. I’ll keep flipping leaves, and if I catch whoever is doing this, you’ll be the first to know.
Meanwhile, the basil in that same container is struggling, with black spots on its leaves, while the oregano next to it is not bothered at all. Laura was not surprised. Oregano tolerates drier conditions than either tomato or basil. Basil is a high feeder that benefits from nitrogen-based fertilizer, and it demands airflow. Even mildew-resistant varieties are still susceptible to some degree. “When we pack those pots together with lots of plants, which is gorgeous, we do increase the chances of having more disease outbreaks,” she said.
Guilty as charged. I have stripped the basil down and left it in place, and as I write this my little plant is starting to recover ever so slowly.
The Rabbit Wars, Continued
Regular readers know the rabbits and I have history. This summer they found my Rudbeckia ‘Goldsturm’ black-eyed Susan, took every leaf and every bloom, and left me the stems. That plant had to go. Its replacement also started to get attacked (see photo) but it is now defended by Plantskydd repellent plus a chicken wire cage, and so far, knock on wood, the rabbits have stopped. For now. I’ve also picked up Liquid Fence so I can rotate that spray with the other. The label says this product uses a scent to repel deer and rabbits so they don’t need to sample the greens.
Laura’s assessment of my defenses was honest. Repellents are meant to smell bad, and in a wet year like this one, every rain washes them away, so you have to reapply right after the rain stops, every time. There is also a theory that animals get used to a scent, so rotating formulations every few applications can help.
The real answer is fencing, and here I learned something. “Chicken wire does not work as well as hardware cloth,” Laura told me. Chicken wire is a thinner gauge, rabbits can bend the tops or jump a short cage, small rabbits slip through the holes, and squirrels fit through them perfectly. Hardware cloth, the fencing with the little squares, is the better defense. Half inch works, but quarter inch keeps more critters out. Not the prettiest look for a patio container, I will admit.
Her final reminder: no plant is truly rabbit proof or deer proof, especially to the young ones, who will try anything at least once. Sometimes that single sample bite is all it takes.
The Four Mistakes We Make in July
I asked Laura what July habits hurt us most later in the season. She had four.
1. Letting weeds go to seed. Every weed that flowers and sets seed contributes to the weed seed bank in your soil, and that can cost you for years. At minimum, deadhead weeds the moment they start flowering. Weeds thrive in adverse conditions; often better than the plants we actually want.
2. Under watering. Much of the state is running dry on the drought monitor, and July heat is unforgiving. Stay on top of it.
3. Under fertilizing annuals. The more we water our containers, the more nutrients leach out the bottom, so keep up a regular fertilization schedule, especially for heavy feeders.
4. Over fertilizing everything else. Many people fertilize their lawns and perennials in July, and for most Minnesotans with cool season turf grasses, this is exactly the wrong time. Those plants are not in active growth right now. “It’s a waste of time and money,” Laura said plainly.
Yes, You Can Still Plant
If your garden has gaps, July is not too late. Laura lights up on the subject of succession planting. She will be harvesting garlic in a few weeks and replacing it with zucchini, plus bush beans and her fall brassicas: kale, cabbage, and kohlrabi, one of her favorites. Storage carrots are another smart July planting. Late July into August, think about a fall crop of cilantro.
The day we spoke, her team at the Minnesota Landscape Arboretum was direct sowing indeterminate tomatoes that produce harvestable fruit within 60 to 70 days, landing them in early to mid September. Just enough runway for a late tomato crop.
For flowers, garden center transplants can add pops of color all summer and into fall. If you are direct seeding, read the packet and choose varieties that mature in 50 to 70 days or less.
Your 15 Minutes This Weekend
If you have just 15 minutes to give your garden this weekend, Laura suggests a “choose your own adventure.”
Look for things ready to harvest, because harvest season is arriving. Cut some flowers that bring you joy; her zinnias are ready. Fertilize if it is due. Or weed.
“Do the thing that brings you the most joy,” she said. “Because if you’re not having joy, being out in the garden isn’t fun and it’s not worth it.”
She finds weeding therapeutic, at least until hour four, which is exactly why she works in 15 minute bites each day. That matches my own patio ritual: a few minutes every morning, finger in the soil, eyes on the leaves. Small, steady attention is how a garden stays known, and a known garden is a healthy one.
Where to Learn More
University of Minnesota Extension offers Minnesota-specific growing guides plus insect and disease identification help at extension.umn.edu. And do not throw away your plant labels. They carry the basics on sun, water, and care. Clip them together in a little binder clip for easy reference.
Laura and I will pick this conversation up again in September. Between now and then, get out there and get intimate with your plants. They will tell you what they need, if you get close enough to listen.
Diana
#bloomwithme
Resources
University of Minnesota Extension Website
My big and only problem is with earwigs. I’ve sprayed with neem oil, dead bug brew, dusted with diatomaceous earth , all to no avail. They keep coming at night and turning my plant leaves to Swiss cheese. I don’t use mulch, keep the patio clean and there’s no debris .. plz help :(
Great tip to look under the leaves. That is exactly where the potato bug larvae is hidden. And so true that those tiny bugs hide where the leaf meets the step.
This is chocked full of great tips.