Share this article

print logo

Fast changes in summer gardens

Change happens fast in our yards and gardens during June and July. Wonderful plants dazzle us with their growth and some soar through their peaks of performance.

Problems also show up quickly: weeds, a few troublesome insects, and several weather-related diseases.

Let’s take a walk around our collective gardens, share some observations, and see if I can answer some questions.

Scabby crabapples

In Western New York yards as well as in Rhode Island, where I toured gardens last weekend, people have been seeing terrible looking crabapple trees. It does not take a plant pathologist – which I am not – to observe evidence of the common disease called apple scab. It affects apple and crabapple trees, particularly when extended wet weather in May and June is accompanied by cool temperatures. (Remember those weeks?) First you see olive green leaf spots that turn velvety, then mottled, then yellow, and then drop.

In a healthy tree the disease isn’t fatal, just unattractive. But are the trees healthy? Last summer’s drought severely damaged many kinds of trees that were not watered deeply. We can expect to see the harmful consequences over many years to come. Some immediate symptoms are poor leafing out and puny leaves this season. Our weather was unusual this spring, with lots of moisture, so some other fungus diseases may flourish as well.

Hummingbirds and penstemons

A wonderful perennial called Penstemon opened recently. The cultivars ‘Husker Red’ and ‘Dark Towers’ are currently popular, with wine-colored leaves and white flowers. If you have planted these (or other plants with tubular flowers) you will probably see hummingbirds.

Do you want to put up a hummingbird feeder? These also attract and satisfy hummingbirds, but there is one important caveat: DO NOT put up a feeder if you are not willing and able to empty and clean it weekly (or twice weekly in hot weather). Molds and fungi grow in feeders, and a particular fungal infection causes hummingbird tongues to swell so they cannot feed and will die. Commit to cleaning or stick with the flowers.

Stippling on herbs and daisies

In June every year gardeners report brownish dots, that later become tiny holes, on the leaves of many perennials and herbs. It looks exactly like stippling with a pencil point. It is evidence of the four-lined plant bug, identified by green and black stripes lengthwise along its body. The bugs suck nutrients from the leaves, leaving the spots behind.

The insects are difficult to see, as they move quickly and hide under the leaves. You may discover the reddish larvae under leaves as well.
Most important to know: their presence passes quickly, and the plants survive very well. While professional growers may use an insecticidal soap spray (under the leaves), unless you are selling or showing these plants, the damage is rarely significant enough to warrant treatment. Usually it’s over before you’ve noticed the damage.

What’s rotting under ground?

Lots of rain produces lots of plant growth. Whether you planted seeds, bulbs, tubers, or bare-root plants, once the seedlings or shoots emerged above ground they probably grew beautifully once the rains came, especially when the sun appeared and the soil warmed up.

However, if seeds do not germinate or tubers produce shoots before an extended rainy period then too much water can cause them to rot. This could happen for your dahlias, cannas, lilies, beans, or potatoes – anything that sat too long in soil that was too wet.

Good rules of thumb for bulbs, tubers, or seeds: Dampen soil lightly but don’t water heavily until shoots appear. Since weather is so unpredictable, stagger planting dates for large crops. If you can, cover raised beds or containers during heavy rainfall, while you’re waiting for plants to get started – and don’t forget to uncover them once the sun has reappeared.

It’s not too late for tomatoes

You won’t have the first homegrown tomato on the block, but it is not too late to plant some tomato plants. Even tomatoes that were planted much sooner haven’t gotten a great start because they must have warm soil to grow well, and sometimes later planting actually catches up.

Choose sturdy plants in the garden center or farmers market, pluck off the first blossoms or tiny fruits (although you won’t like doing it), and plant them in great potting mix in containers or in compost-rich soil.

It’s also smart to plan your staking, propping, or tying method for tomatoes. New gardeners often underestimate how large tomato plants will grow. You might get the impression that small tomatoes grow on small plants.

But surprise! Those innocent-looking cherry tomato plants may grow to be 5-foot giants that topple your puny cages. Read plant labels for the expected size.

Plants marked “determinant” or “patio tomatoes” may stay small, but “indeterminate” tomatoes will become large. Get bigger cages, or do some research about tomato propping methods such as the stake-and-weave approach.

Did the J.B.s drown?

I am offering hope and a scientifically unsubstantiated opinion here: I think that many Japanese beetles may have drowned during the prolonged rainy period during late May and early June. The beetle grubs spend winter several feet below ground and move upward during spring. The soil was deeply saturated in many areas as those beetles moved closer and closer to the surface. It has happened before, and it may be the case this season, that many will never emerge to eat our flowers. We’ll know soon.

Let’s welcome July with our garden gloves on and our eyes wide open. What an exciting season it is!

Sally Cunningham is a garden writer, lecturer and consultant.

There are no comments - be the first to comment