May can be one of the most diverse months for those who garden. While last May was almost entirely damp and cold, some years, it will warm up early and stay that way. There can be years when the month is dry, or it could be full of excessive rain. While the average for the last frost is around May 10, we can also get frost as late as Memorial Day.
Generally speaking, it is safe to plant everything in the garden by the end of the month. At the end of May, we are officially at the “Let’s plant everything” part of gardening season.
Right now, gardeners are questioning if it is safe to plant anything yet. I think that they feel that any cold temperatures will hurt all plants. But trees and shrubs are very tolerant of the cold. You can plant them from late March until early November. Perennials can also be planted in April, and there are vegetable plants that are cold tolerant. These would include lettuce, spinach, peas, broccoli, cabbage, Brussels sprouts, cabbage, cauliflower, kale, beets, radish, carrots, onions and potatoes.
I may have forgotten a few, but I deliberately left out tomatoes, peppers, squash, cucumbers, eggplant and basil. These are all plants that have their origins in more tropical climates. If you plant these plants before the last average frost date, you run a big risk of losing them to a frost.
It is best to be a bit conservative when it comes to planting your vegetable garden.
Questions are also raised about when to plant annual flowers. Gardeners want to plant the impatiens as soon as possible. But there are so many tender annual flowers that I can’t list them all here. You must realize that most annuals will be killed by a frost. You are better off waiting until later in the month to plant them. Still, there are some annual flowers that will tolerate cold temperatures. Again the list would be too long to be included here. At the store, we try to bring in only the annual flowers that we think it will be safe to plant at any time during May.
The warm weather in March has made many shrubs flower early this season.
As the spring flowering trees and shrubs have finished their blooming time, you should now give the plants some fertilizer. This will help the plants to put out new growth and to help them to set their flower buds for 2013.
Quite a few of you have noticed damage to the new leaves of your trees. The culprit appears to be the caterpillar of the winter moth. This caterpillar can do a lot of damage in a short period of time. An effective control for this stage of the caterpillar is an application of a product called BT. This is a bacterium that kills caterpillars, yet won’t harm other beneficial insects. It is mixed with water and sprayed onto the leaves of the plant. The caterpillar will still consume a bit of the leaf, but very quickly it will stop eating and die within a few days. There are other products you can use, but this is probably the most effective.
Well, that’s all for this week. I’ll talk to you again next week.
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Tim Lamprey is the owner of Harbor Garden Center on Route 1 in Salisbury. His website is www.Harborgardens.com. Do you have questions for Tim? Send them to ndn@newburyportnews.com, and he will answer them in upcoming columns.
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