HOURS: Scandia and St. Croix Falls locations: Mon - Fri: 10am - 6pm | Sat: 9am - 5pm | Sun: 10am - 4pm | Stillwater location closed for the season
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Scandia
(651) 433-2431
20021 St Croix Trail N
Scandia, MN 55073
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St. Croix Falls
(715) 483-3040
1257 State Rd 35 St
St. Croix Falls, WI 54024
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Stillwater
(651) 439-2140
2100 Tower Dr
Stillwater, MN 55082

May Lawn And Garden Calendar

May Lawn And Garden Calendar Image

May Lawn And Garden Calendar

CLICK HERE for the downloadable PDF.

Annuals
● Most annuals can be planted late May, depending on the weather forecast. It may be a good idea to harden off plants grown indoors before planting them by leaving them in their pots outside. Bring them into the garage on cold nights. 
● Some seeds, including cleome, cosmos, snapdragons, and morning glory vines can also be started in late May.
Bulbs
● Prepare the soil by adding organic matter to the top 8-12” before you plant any bulbs. 
● Add a slow release fertilizer (1 pound per 100 square feet) when planting. 
● When the soil warms (this usually happens by the end of May) you can start to plant gladiola, caladium, cannas, callas, and dahlias. 
● Begin deadheading faded flowers on the spring blooming bulbs. You can also start using the blooms for cut flowers.
Fruits
● Continue to plant. It is now safe to plant blueberries. 
● Replenish wood mulch around fruit trees, shrubs, and grape vines. Add shredded leaves to raspberry and strawberry plantings to keep moisture in and weeds out. 
● Check new plants twice per week for water. The plant will need water if the top 4" of soil are dry. Newly planted fruit trees need about 3-5 gallons of water each week. Established plants need about an inch of water per week. 
● Fertilize raspberries with 1 cup of ammonium nitrate per 100 feet of row. Also, give blueberries about 2 tablespoons of ammonium sulfate about 2-4 weeks after planting. 
● Continue to spray fungicide for apple scab. Remove fire blight infested branches and webby nests of tent caterpillars. Do not spray plants with insecticide while flowering. This will kill nature's pollinators and can prevent fruit set.
Herbs & Vegetables
● It is now safe to plant seeds of beets, carrots, chard, kohlrabi, leaf lettuce, onion sets, parsnips, peas, potatoes, radishes, spinach and turnips. 
● It is also safe to plant parsley, head lettuce, early cabbage, broccoli, brussel sprouts, kale, and onion. 
● By the end of May, it is safe to plant muskmelons, pumpkins, winter squash, celery, and cucumbers. 
● Begin to harvest three year and older asparagus plants when they reach 6-8” tall. You can also start to harvest two year and order rhubarb plants when they reach about 12”. 
● Water new plants and seeds regularly. Keep the 2-3” of soil moist to encourage deep rooting.
Lawns
● May is still a good time to plant sod and lay seed. Keep newly planted grass moist. 
● Rake out dead grass. If there are heavy amounts of dead grass, it may be a good idea to dethatch your lawn. Do it now or in the fall. 
● Established grass needs about 1" of water per week. Usually you will not need to water in May, unless it is a very dry spring. 
● Treat creeping charlie when it is in full bloom with a broadleaf weed killer containing 4D and MCPP. Spot treat areas only.
Perennials, Ornamental Grasses & Groundcovers
● Continue to plant. All perennials are safe to plant in May. 
● Dig up and divide summer and fall blooming perennials. 
● Remove unwanted perennials seedlings. Black-eyed susan, purple coneflower, and other prolific seeders may have provided more offspring than you wanted. Dig the undesirable areas up and share them with friends. Put stakes, peony cages, and trellises in place. 
● Water new plants well. Established plants will not need much water at this time. 
● Thin out bee balm, garden phlox, and other perennials that are susceptible to powdery mildew. Shear creeping phlox to encourage a new flush of growth. 
● Begin deadheading early blooming plants. 
● Pull weeds as soon as you see them. 
● Perennials generally do not need any fertilization, but if you can tell they need some extra nutrients, use a balanced liquid fertilizer one time in the spring.
Roses
● Continue to plant. 
● Begin to monitor water needs. Established roses need about 1” of water per week. 
● Fertilize shrub roses. Apply 2 tablespoons of a low-nitrogen, slow release fertilizer per plant. 
● Begin checking for pests and disease.
Shrubs
● Continue planting. 
● Shrubs need little fertilization. Wait 2 years after you plant the shrubs to fertilize them. Use a slow release nitrogen fertilizer. 
● Check your mugo pines for sawflies. 
● Water if needed. Try to water less frequently but thoroughly, getting the top 6" of soil wet. 
● Prune spring flowering shrubs that are done blooming. Remove faded flowers on lilac and rhododendrons to encourage better flowering next spring.
Trees
● Only prune to control disease and damaged branches. 
● Fertilize only if needed. If you already put down an application in April, no need to this month. 
● Give trees a mulch ring. The bigger the ring is, the better it is for the tree. 
● Established trees will probably not need any water, unless it is a very dry spring. Newly planted trees may require water. Check the top 6” of soil and water if it is dry. 
● Remove tent caterpillar nests. Begin watching for other pests and diseases.
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