Master Gardener Sue Morris: Eradicate poison ivy, some answers to this year's vegetable woes
Control of poison ivy and poorly yielding vegetable gardens are the topics of this week’s Master Gardener column.
When you are out communing with nature, keep a watch out for poison ivy. It is a perennial plant that often is low growing between 1 to 2 feet tall but can also be a climbing form and can be 3 to 12 feet or more in length.
“Leaves of three, let it be” is a place to start when it comes to identification. Leaves tend to be 2 to 7 inches long and 1 to 4 inches wide with an egg-shape.
They have a pointed tip and smooth to slightly irregular toothed edge. They have a strong mid-vein running up the center with smaller veins evenly spaced at a 45-degree angle.
These leaves are glossy-green with a possible red-purple hint in early season. In the fall the leaves turn yellow to red. Some plants will produce a cluster of white to cream colored berries. The plant spreads by its roots, above ground vines or berry distribution.
Beth Berlin, Extension Educator with the University of Minnesota, tells us to control poison ivy look for herbicides containing triclopyr. It is often under labels specifically for poison ivy or a woody brush killer. Apply when temperatures are 60 to 85 degrees. Read and follow all label directions.
Avoid spraying on windy days to prevent drift. Reapplication may be necessary a few weeks after initial treatment as it is a tough plant to kill and may re-sprout. Do not treat in the fall but when actively growing.
Vegetable garden woes
We have heard from the University that Extension educators across the state are getting many questions about poorly yielding vegetable gardens. Marissa Schuh, Extension educator in integrated pest management, has some answers for gardeners.
Bushy cucumber plants with no fruit, tomatoes not ripening, and beans with no flowers.
Persistent high temperatures are mostly to blame.
If you have lots of green but no vegetables, you might be giving too much nitrogen.
If you are seeing flowers but aren’t getting fruit, it might be flower abortion — this happens at temperatures from 75 to 95 degrees. Tomatoes only have a 50-hour-long window in which to be pollinated and if not pollinated, flowers drop off.
Vining vegetables in the cucurbit family (pumpkins, squash, melons, cucumbers, and the like) produce male and female flowers. Look at the base of the flower to tell the sex.
Female cucurbit flowers will be swollen underneath in the area that will eventually become the pumpkin, zucchini, etc.
Male flowers will have just a straight stem.
Depending on the variety of the vine crops, hot temperatures can change how many male and female flowers are present and might develop more male flowers than female flowers. Female flowers produce the fruit.
Cucumbers develop odd and uneven shapes when not fully pollinated. In crops that depend on pollinators, such as members of the vine crop family, hot weather can impact bee activity, causing reduced fruit set. Just as we like to take it easy and rest in the shade on a hot day, so do many bees.
The ideal range for pollination for many species of bees is somewhere between 60° and 90° F, with hotter temperatures in this range promoting more pollination. Once it gets over 90° F, many bees slow down and pollinate less. This can be especially pronounced in crops like cucumbers, whose small flowers aren’t particularly attractive to many bees.
Pollination may occur, but not at a high enough level. This can lead to deformed cucumbers, summer squash and melons.
You may have noticed small squashes, pumpkins and melons forming but then rotting. A common cause is poor pollination. This is another cause of fruit that forms and then quickly dies.
Green beans can have similar issues. During periods of hot weather bean flowers produce less pollen, which cascades into fewer, smaller pods containing fewer, smaller beans.