Instead of ushering in the summer season, as is usually the case, this past Memorial Day weekend featured a return to winter like weather. I don’t ever recall such nasty weather this late in the season. Some people lost some tender vegetable garden plants from the cold. As my friend Ken, from Story’s nursery says “Plant early and be prepared to plant often.” I lost one of my “Big Beef” tomato plants and I am glad I did not set them all out yet! The rain was more than welcome though, as I recorded almost 2.5 inches at my house. My rain barrels runnith over!
It looks like many of us will spend some time this week mowing our lawns as our cool season grasses grow fastest under precisely these cool, wet conditions. Normally, I would be reminding you that this is a good time to fertilize your lawn as well as applying herbicides to kill dandelions and other broad leafed lawn weeds, but with 90 degree temperatures predicted for the weekend and into next week, there is a danger of chemical “drift” that can harm your garden plants. Certain lawn weed killers, which contain the herbicide 2-4 D, may volatize when the temperature exceeds 85 degrees. That means they produce an invisible “gas” that can “drift” and damage plants 50 feet or more from where they are applied. Best to wait on the weed killers and even the fertilizer until it cools down once more. Grass plants shut down photosynthesis when it gets too hot, so fertilizer may be wasted if applied in really hot weather.
Several of you have inquired about a problem with your peach tree leaves. The newly expanded leaves are curled, deformed and distorted with odd, pink, colors and swellings evident. This is called “peach leaf curl” and it is caused by a fungus that overwinters on the branches and twigs of your peach tree. It looks terrible, but fortunately it does not generally affect the fruit at all and the damage is mostly cosmetic. It cannot be treated now and like all fungal diseases, it cannot be cured once infection occurs. It must be prevented and the time to apply a preventive fungicide is late fall, after the leaves drop or early in the spring before they appear. It also helps to rake up fallen leaves in the fall and dispose of them.
My peach trees have set a huge crop once more, thanks to my hummingbird friends who arrived just in time to pollinate them! I have not seen a single honeybee this spring, but I don’t recall ever seeing as many bumblebees as I have seen! Most of the bumblebees I am seeing are carpenter bees and they are drilling numerous holes in my soffits around my sheds. At times it appears to be raining sawdust beneath the sheds. I have had to resort to applying an insecticide to the exposed wood surfaces to deter them and I will be filling in the holes with wood putty for the rest of the season.
Those of you trying to grow backyard tree fruit need to be diligent with a spray routine until at least mid-July. Apples are most susceptible to insect and disease pests followed by pears, then cherries, peaches and plums. It is sometimes possible to get a good crop of peaches or plums without spraying at all. The most common and serious problem with plums and cherries is a disease called black knot. This is also caused by a fungus that gets inside the branches and causes them to grow a black, swollen area. The leaves and twigs beyond the swelling die and no fruit will ripen on them. You should prune off these infected twigs at least six inches below the swollen area. Sometimes these black growths, called “galls” will form on a main trunk and that often signals the end of the tree, but I have seen many severely infected plum trees still produce a decent crop of fruit with dozens of galls on it. Once more the fruit is unaffected.
The biggest problem with pears is a bacterial disease called “fireblight.” It causes the ends of twigs to wither, turn black and die. It appears as though the infected twigs were burned with a blowtorch! Infection only occurs during rainy weather when the tree is in bloom. Bacteria enter the twigs through the flower blossoms and if it is hails during the bloom period, the infections are generally much worse. It does not happen every year, except to the most susceptible varieties and sometimes this disease affects apples as well. Pruning off the blackened tissue is your only recourse. Commercial pear growers will usually apply an antibiotic spray of Streptomycin as a preventive when conditions warrant it.