Garden Clippings: May is the Month to...

• Plant tender flower, vegetable, and melon transplants. The party line is to wait until ‘danger of frost has passed’, making Memorial Day weekend the traditional annual target for many folks. Taking a gamble by choosing to transplant earlier is a matter of personal preference, but comes with the responsibility of being ready to protect seedlings if frost threatens. For the best start possible, harden off plants grown in warm environments by gradually increasing exposure to full sun and cool nights over a 7-10 day period before transplanting. Plant on a cloudy day to further reduce transplanting stress.
• Think about grub control. For lawn areas that have a history of grub problems, preventive applications are often the best approach for keeping populations below damaging levels. The idea is to have the material in place when grub eggs hatch (typically mid-July through mid-August), thereby contacting the grubs when they are most vulnerable. Preventive products that contain chlorantraniliprole (AceleprynTM) as the active ingredient take 60 to 90 days to fully activate in the soil, so are therefore best applied during the month of May. Preventive materials with neonicotinoid active ingredients (eg. imidacloprid) take much less time to activate and are best applied in July.
• Scout Asiatic lilies for bright red Lily Leaf Beetle adults, along with characteristic ragged feeding holes on the leaves. Hand picking and destroying adults can be an effective strategy for smaller plantings, while a pyrethroid insecticide may be more convenient for control in larger plantings. Eradicating beetles in the adult stage will reduce numbers of future larvae, which are the most potentially damaging life stage of this pest.
• Harvest asparagus. Spears are ready to cut when they reach 7”-10” in height and before the heads begin to open. Letting heads open too much will yield tough spears. Do not harvest or harvest very sparingly for the first two growing seasons that asparagus is in the ground. After, follow the ‘2-4-6 sequence’: harvest for two weeks the third year, four weeks the fourth year, and six weeks the fifth and following years. A well-tended asparagus bed can be productive for 25 years or longer.
• Set up hummingbird feeders for the season. Hummingbirds return to Massachusetts by late April/early May in most years, so plan to have feeders in place and filled by the first week in May, if possible. Your best bet for a nectar solution? 1 part cane sugar to 4 parts water, boil until sugar is completely dissolved (1-2 minutes), and cool completely before use.
• Begin eradicating Japanese knotweed. With some effort and patience, repeat cutting is an effective strategy for management of this invasive species. The process involves regularly removing the knotweed shoots with the goal of eventually depleting the underground rhizomes that allow the plant to regenerate. To begin, mow or cut the top growth when it reaches a height of 4-6 inches, and then cut again and as often as the 4-6 inch threshold is reached.
• Work out your watering routine. May is a great month to get out those watering cans, set up sprinklers, work the kinks out of drip systems, and develop a good regimen for keeping your plants well hydrated in the warmer and drier months ahead. Get in the habit of checking soil moisture levels regularly, and watching plants for signs of wilting or other stress. When you do water, aim for deep and infrequent as opposed to shallow and frequent. Water slowly to allow water to infiltrate and avoid puddling and runoff. Remember to account for weather factors such as rainfall or extreme heat, and adjust watering accordingly as the season progresses.
• Apply mulch. Organic mulches offer many benefits for landscape plantings, including moisture retention, buffering of soil temperature fluctuations, weed suppression, and the addition of organic material into the system. Choose mulches with high bark content to discourage the development of artillery fungus. Avoid mulching too deep (4 inches max), and don’t allow mulch to contact the bark at the base of trees or shrubs. Mulching in spring will smother young summer annual weeds, and prevent new ones from germinating, but it is best to remove established perennial weeds before mulch is applied.
• Deal with pine pollen… ugh! May is normally peak season for the onslaught of everyone’s least favorite, seemingly relentless yellow dust. While pine pollen is much less prone to affect allergy sufferers than other plant pollens, it is otherwise a major nuisance. Wetter weather helps to keep the pollen out of the air, while drier conditions lead to more problems. What to do? Put off painting projects, dust a little more frequently, wash the car a couple of extra times, and take solace in the fact that the worst of it only usually lasts about two weeks.
• Consider a perimeter treatment for ticks. If ticks are a problem on your property, it is normally not necessary to treat the entire site. Treatment of the just the shady, leaf littered perimeter areas with a spray or granular application is normally highly effective at reducing tick encounters. A series of two applications is the recommended approach: once in mid-May and again in mid-June. Perimeter applications are best carried out by a properly licensed professional applicator with specialized equipment.
• Patronize your local garden center. The month of May, with spring planting in full swing, Mother’s Day and Memorial Day, is often the most important month of the year for garden centers in terms of the bottom line. Visiting in May, therefore, is typically a win-win… the garden center gets your business, and you get the best they have to offer in terms of selection and service.
• Bring a bouquet of fresh cut lilacs into the house. Research suggests that certain aromas make us happy when we associate them with positive events and experiences. With a scent that celebrates the glory of spring and confirms that winter is now just a memory, you can’t lose!

Author: Jason D. Lanier, Extension Educator

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