Master Gardener Sue Morris: How has your rhubarb been growing this year?
Rhubarb season is almost over but it is time to mulch tomatoes, continue deadheading flowers and fertilizing pots of annuals.
How has your rhubarb been growing this year?
The early and heavy rains we had in May seemed to produce a heavy crop of rhubarb. I don’t think I’ve ever had rhubarb produce seed as early or as frequently as this year. Seems every time I walk by the plants there are several more seed heads sticking up, no matter how often I remove them.
Do you pull your rhubarb stalks or cut them off?
You should pull the stalks, as when they are cut off — what is left of the stalk will rot and not do your plant any good.
Grab the stalk and slightly twist and pull. Usually, rhubarb should not be harvested after the first of July in order that the plant might store reserves for the following year.
Some have thought that rhubarb gets poisonous this time of year. That is not true. In hot weather, the stalks aren’t fresh and crisp and tasty this time of year.
Beth Berlin, University of Minnesota Extension, reminds us that rhubarb contains high levels of oxalic acid. Too much oxalic acid in the human body can tie up calcium and make it unavailable to the body.
However, eating rhubarb desserts occasionally will not cause a serious nutrient deficiency. People with gout or a history of kidney stones should consult their physicians before consuming foods like spinach and rhubarb that contains high levels of oxalic acid.
Remember to keep deadheading flowers as they finish their bloom. A plant’s purpose is to flower and set seed. By deadheading, you will prevent seed from setting and the energy that would be used to produce seed will now go back into the plant, making for a healthy plant for the coming year. Daylilies especially look much better if they are kept deadheaded.
Continue to fertilize your pots of annuals as watering has a tendency to leach out the fertilizer. Water weekly, weakly — half strength of a liquid fertilizer is good. Be sure to water all your pots with plain water first. Then go back and water with the fertilizer mixture. This prevents the fertilizer from draining out without any benefit to the plants.
Annuals can be fertilized right up until frost. Perennials shouldn’t be fertilized after Aug. 1 as they need time to slow down and prepare for winter.
By now you should have mulched under your tomato plants. Mulch is the best way to preserve moisture in the ground.
Mulching under your tomato plants is also one of the best ways to prevent early and late blight, as that way when you water or it rains, the spores from the ground don’t have the chance to splash up on the lower leaves and start blight.
Word of caution, don’t mulch with grass clippings if you have treated your lawn with a chemical for weeds until you have mowed several times after treating.
Master Gardener Sue Morris has been writing this column since 1991 for Kandiyohi County newspapers. Morris has been certified through the University of Minnesota as a gardening and horticulture expert since 1983. She lives in Kandiyohi County.