July garden checklist

UNIVERSITY OF MINNESOTA EXTENSION - www.extension.umn.edu

Mystery of the month

What in the world happened to this strawberry?

The answer is at the bottom of this article.

Pests and diseases

Scout your plants for Japanese beetles. Japanese beetles start emerging in earnest in July. They are slower in the mornings when temperatures are cooler. Simply flick them into a bucket of soapy water to remove them.

If you see a white spot on their head or back that seems out of place, don’t flick them into the bucket! They have been parasitized by the Winsome fly. The Winsome fly will eat its way through the beetle and continue to increase its population if we leave the infected beetles alone.

Trees and shrubs

Check trees and shrubs for signs of drought or flooding stress. Some areas of the state have been getting lots of rain, which can suffocate roots.

Other areas are in desperate need of some rain. If you are in an area where rain has been few and far between, make sure to water your established trees and shrubs to keep them healthy in the long term.

lowers and other garden plants

Thin overcrowded plants in July. You may be seeing more powdery mildew, which can indicate excessive humidity in the plant canopy (where the leaves grow). If your plants are too crowded together, humidity increases, and this may cause more severe disease outbreaks.

Some plants, like many bee balms, are highly susceptible to powdery mildew, regardless of how close they are to other plants.

Powdery mildew is generally just an aesthetic issue and not usually the reason a plant will die.

Houseplants

Dump those drip trays after a heavy rain! If you put your houseplants outside for the summer, don’t let them sit in standing water. The roots or crowns of the plants may rot over time, particularly with the warm temperatures we have been having.

Lawn

Most of our lawn grasses slow or stop growing when air temperatures reach the high 80s or low 90s. Normally, at these temperatures, the lawn doesn’t need to be mown, but you may notice that grasses in the shady parts of your lawn are still growing, and you might be tempted to mow.

Turfgrasses tolerate mowing better than any other plant species, but it is still a stressor for them, especially at temperatures above optimal. When the forecast shows temperatures above the mid-80s for several days, it is probably a good idea to hold off on mowing.

If there is a break in the high temps, just mow the areas that have grown and need it. In many cases, you can relieve summer stress on your lawn by doing nothing.

See Conserving water on drought-affected lawns and Mowing practices for healthy lawns.

Other tasks

Harvest garlic this month, and consider planting something where it was, like another food crop, cover crops, or flowers. You can also do this in any area where you previously grew plants, such as bush beans or lettuce. Some shorter to maturity (or flower) plants include:

• Spinach
• Kale
• Radishes
• Beets
• Carrots
• Marigolds
• Calendula
• Alyssum

See Extending the growing season.

Solution to the mystery of the month

Strawberries are considered accessory fruits because the red and white fleshy parts are not actually part of the ovary, which is where most fruits come from. A single strawberry is actually made up of many fruits that are fused or aggregated together. Other aggregate fruits include raspberries and blackberries.

The black or yellow dots on the outside of the strawberry are the true fruit! We commonly call them seeds, but really, the seeds are within those tiny yellow or black dots.

So, what’s up with this mystery strawberry? The seeds germinated while still attached to the fruit! This phenomenon is called vivipary, in which seeds germinate in or on the fruit. You may have seen this when you cut open a tomato, pepper, or squash, and you saw green growing inside the fruit.

A normal red, ripe strawberry

A tomato with some germinated seeds inside