The Dirt / A garden year in review
Potted plants can suffer from too much rain.
It was a very good year, according to many growers and gardeners. In 2017, rainfall was abundant and just frequent enough that we didn’t have to water often. Just before they were doomed to be ripped out for failure to bloom, many bigleaf hydrangeas sprouted masses of pink and blue flowers—at long last! Daylilies and hostas loved the generous water, and many other perennials grew taller and bloomed sooner than usual, many just in time to perform like divas for our garden walks, tours, and the GWA (Garden Writers Association) conference.
Yes, it was a good season, unless you were a tomato, lily, begonia, or peony.
Too much water or too little heat
In gardening, it’s always about the excesses and deficiencies. Indoors or out, most plants die from too much or too little water, and we often saw extensive rainfall during June and July. This season, the fastest way to kill a begonia was to leave it in a basket outside during heavy downpours. That may be equally true of fuchsia, succulents, licorice plant, or any other potted annual that needs to dry out between soakings. If those plants were protected under picnic tables or other shelters during the downpours, great. Otherwise, many roots and stems went soggy and rotted.
Some plants just wanted to be in Virginia. While tomatoes do like a lot of water, they also grow bigger and better with lots of sunlight as well as heat. That’s why many gardeners grow them in black plastic pots, or surround them with dark plastic that holds the heat. Also, lots of water washes the nutrients through raised beds, pots, and even the soil, so nutrient-guzzlers like tomatoes may have missed some of the nutrients that make the fruits large and tasty.
In August, one of the questions I heard often was: “What’s wrong with my cannas? I planted them in nice potting mix/brought them up from the basement at the usual time—and no flowers yet!” The answer again was not enough sunlight, not enough heat. That answer may have sounded foolish to people sweating in the sun as they asked the question, but think back: how many nights in July and August were actually hot?
The happiness of the fungi
In the disease triangle, you need the right plant (target), the right pathogen (fungus in this case), and the right conditions (wet or humid weather). We had them all. Many lilacs and peonies turned silver with powdery mildew after an extended damp June (especially those in partial shade with poor air circulation and crowded branches). Many bee balms (Monardas) and some roses followed suit. You might have noticed that a peony looked mildewed right next to a lilac that did not: that’s because
a) some species or cultivars of many plants are more resistant than others, or
b) powdery mildews come in specific strains that attack specific plants. Most diseases are species-specific; one doesn’t “catch” a mildew from a different plant species. Finally, every plant in every yard has its own life experience; one gets more heat and breezes, more water or less crowding. All the plant pathology reports were not in or assessed at land grant colleges as this article was filed, but individual reports included several other diseases in vegetable crops, including downy mildew on cucumbers and Phytophthora (late blight), blackleg, and bacterial diseases in potatoes—directly related to extended rain events. In my experience, powdery mildew is the norm on the leaves of squashes and other vine crops—usually after we are picking the vegetables—and this year was no exception.
Among the ornamental trees, a couple of other fungi showed their nasty, sporulent faces. Apple scab turned many crabapples ugly this year, quicker than usual. You probably noticed mottled gray/browned leaves that dropped early. The disease also ravaged many apple trees, deforming the leaves as well as the fruit in susceptible varieties. Scabs are entirely predictable after a wet spring, but many varieties of disease-resistant ornamental crabs as well as apples are now available. If you have a susceptible tree, know that the disease does not kill otherwise healthy trees, but can look terrible. If you’re sick of it, replace it. For prevention, you may decrease next season’s apple scab by raking up and destroying the leaves that fall this season (where the spores hang out), but if there are crabapples and apples in your neighborhood or woods—don’t bother. (For prevention and management of this or any other disease, start with the Cornell University Integrated Pest Management Department: nysipm.cornell.edu.)
Other tree diseases that thrive after moist periods are horse chestnut leaf blight and tar spot on Norway maples. These are basically unmanageable by a homeowner without significant investment, and I suggest a philosophical approach: this too shall pass.
The beetles and the slugs
I asked and asked, in my travels among gardeners: do you think that even the slug eggs drowned? I personally didn’t see slug damage until the middle of summer, and I had not made any effort at prevention. Most serious gardeners using hostas do something to prevent/kill them, whether it’s a product (like Sluggo), handpicking, or the myriad other choices (beer-dish/copper strips/diatomaceous earth). I like Marcia Sully’s method (Hidden Gardens of Eden). She broadcasts Milorganite (a processed biosolid that has repellant properties) liberally early in the season and her gorgeous hostas—in deer country—attest to its effectiveness.
Japanese beetles were not abundant, according to at least forty gardeners I surveyed (about five declaring the opposite). I am sure that the larvae, in saturated soil during May and June, mostly drowned before they emerged. It’s a good reason to cheer for a sopping wet spring.
One beetle must be reported as increasingly present in WNY: the lily leaf beetle has arrived in at least half the gardens visited. You’ll know it on lilies—Lilium (not daylilies)—when you get it. A Connecticut garden writer who lectures on just this pest said we shouldn’t stop planting lily bulbs (my inclination). She stressed the importance of getting ahead of the pest early by scraping off the egg masses on the undersides of lily leaves in April or May, and then continuing to handpick the larvae. Later, stir up the soil at the base of the plants, after the larvae are seen no more, as they will be there pupating and then emerging to feed again as adults. Some products are labeled for this pest, but, as an organic gardener, I won’t use them. It is encouraging to know that lilies aren’t necessarily gone from all our gardens into the future.
Whether the plant is a crabapple or a lily or a rust-riddled hollyhock, a gardener just has to decide what the plant is worth to her and what she is willing to do.
So, was it a very good year? The answer is subjective and dependent on what you grow and how attentive and flexible you are about adjusting to seasonal conditions. We will have some very dry periods and very wet times in the garden seasons ahead. The key is to know what to do to help certain plants through unfavorable episodes (put that begonia under the table), and to change the conditions that favor a predictable pest or disease (thin the crowded lilac branches and move the bee balms to a breezy area). It helps (and is mentally healthy) to develop tolerance and drop the illusion that all plants will look perfect all the time.
Then understand: responding to the exigencies of weather and inconvenient pests is part of gardening. Theoretically, we get better at it every year.
Sally Cunningham is an organic gardener, CNLP (nursery/landscape professional with PlantWNY), garden book author, part-time consultant with Lockwood’s Greenhouses, and tour director with AAA/Horizon Club Tours.