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The following gardening calendar was created with help from two of our favorite gardening reference books: Month by Month Gardening in Wisconsin: What to Do Each Month to Have a Beautiful Garden All Year by Melinda Myers and The Wisconsin Garden Guide – The Complete Guide to Vegetables, Flowers, Herbs, Fruit, & Nuts, Lawn & Landscaping, Indoor Gardening by Jerry Minnich.
Early May
· Lawn care: 
o Mow lawn frequently, keeping it at a 2 to 2 ˝ inch height. Mow often enough so that you are not removing more than 1/3 of the total height at a time.
o Fertilize lawn with Stein’s Weed Control plus Lawn Food® to decrease dandelion and broadleaf weeds.
o This is the best time to seed or over-seed your lawn. Use Stein Premium Coated Grass Seed Blends specially formulated for Wisconsin lawns. It is also still a good time to sod.
· Gardening:
o Start the following seeds indoors: melons, squash, cucumbers and pumpkins.
o Plant the following outside in your garden: parsley, head lettuce, cauliflower, broccoli, Brussels sprouts, red and green cabbage, collards, kale, kohlrabi and onion plants.
o Water your garden early in the morning to reduce water evaporation and the risk of disease.
o Harden off plants that were started indoors before planting outdoors.
o Install a garden fence to keep rabbits out. You can also try a repellent such as Bonide Repels-All®.
o Place netting or season-extending fabric over garden to further protect plantings from birds and animals.
o Begin to harvest asparagus (only harvest 3 year and older asparagus plants when the spears reach 6 to 8 inches long).
o Begin to harvest rhubarb (harvest two year old plants for one or two weeks. Older, established plantings can be harvested for 8 to 10 weeks). Pull or cut the thick, crisp leaf stalks when they are 12 to 15 inches high. Just use the stems; remove the leaves as they are toxic. Remove rhubarb flower stalks as they weaken the plant.
o Cover strawberry blossoms if temperatures threaten to fall below freezing.
· Plantings:
o Transplant summer and fall blooming perennials if the tip growth isn’t too tall.
o As a general rule, avoid moving woodland wildflowers as they do not like to be transplanted. If you do move them, do so after blooming.
o Once every two years, top dress planting beds with several inches of compost
o Incorporate organic matter when planting perennials and annuals because it helps conserve moisture and reduces weeds.
o Interplant annuals among spring-flowering bulbs.
o Plant Iris, potted rose bushes, bush fruits such as raspberries, blueberries and grapes,
o  Roses: Plant potted rose bushes, clean up dead leaves and debris near roses, fertilize old garden, shrub roses and climbers once buds begin to swell.
o Plant fruit, balled and burlapped, and container-grown trees.
o Set Easter Lilies in your garden. The bulbs may not bloom until mid to late July of the second summer after transplanting.
o Plant and transplant evergreens.
o Prune mugo pines by pinching or cutting out two-thirds the length of the “candles” of new growth.
o Disbud peonies. Remove secondary buds off of the primary bud for larger blooms.
o Check columbine for pests such as leafminer, columbine sawfly and stalk borer.
o Prune honeylocusts once the leaves have fully expanded.
o Remove European pine sawflies from mugo pine by smashing them with a leather glove-clad hand or prune out and destroy the infested branch.
o Treat mugo and other pines that have pine needle scale. Apply Safer® Brand Insect Killing Soap when the Vanhoutte or bridal wreath spireas are in bloom and again 7 to 10 days later.
o Watch for phomopsis blight on junipers and Russian olives especially during cool, wet springs. Infected plants have sunken discolored areas with brown and dead needles. Prune out infected branches 9 inches below the canker, disinfecting your tool between each cut.
o Remove and destroy webbed nests from Eastern tent caterpillars on crabapple, birch and other ornamental trees.
o Find and destroy gypsy moth larvae on trees. These worm-like insects grow to be 2” long and are defined by two rows of red and blue warts on their backs.
o Watch for fireblight on crabapple trees. The leaves turn black and branch tips will curl. Avoid pruning crabapple trees during wet periods. Prune out infected branches below the canker (sunken, discolored area) on the stem. Always disinfect tools between cuts.
o If Iris borer is a problem apply an insecticide once the foliage reaches six inches tall. (It is not effective if applied later than this).
Mid-May
· Lawn Care:
o Continue to water newly seeded grass.
o Use Bonide Weed Beater ULTRA on your lawn to eliminate tough weeds (Note: it could take several years to eliminate the offspring of these weeds).
· Gardening:
o Plant the following seeds outside: Brussels sprouts, snap beans, sweet corn (stagger these 5 days apart for a longer harvest), late cabbage, and pole beans
o  Pick strawberries 30 days after strawberry blooms appear.
o Cover broccoli, cabbage, turnips, and radishes with gardening fabric to keep harmful insects away.
· Plantings:
o Plant flowering annuals once the danger of frost has passed.
o Transfer flowering annual seedlings to your garden. Make sure to harden them off first by placing them outside in a sheltered location one week prior to transplanting them.
o  Plant gladiolus bulbs every week from now through June for continuous blooms later in the season.
o Pinch back mums and asters and keep them at 4 to 6 inches tall now through June.
o Remove faded tulip blooms, but do not cut surrounding foliage until it turns brown.
o Stake peonies and delphiniums for optimal growing.
o Plant container gardens making sure to water them daily and feed them Osmocote® Smart-Release® Plant Food.
Late May
· Gardening:
o Plant the following seeds now: tomato, pepper, eggplant, melon, and squash. Cover them if there is a late frost.
o Stake or cage tomato plants before their vines fall to the ground.
o Place transplants of pumpkins, winter squash, muskmelons, celery, and herbs outside in the garden.
o Sow seeds of strawflowers for use as dried flowers next winter.
o Sow lima beans, cucumber, melons, and summer squash seeds. Select short season varieties of squash and melons that will reach maturity before the first frost.
· Plantings:
o Prune spring flowering shrubs (i.e lilac, forsythia) as soon as they are done blooming.
o  Shear creeping phlox (Phlox subulata), pinks (Dianthus), and candytuft (Iberis) after they flower to encourage new green foliage.
o Pinch back shasta daisy (Leucanthemum), tall garden phlox (Phlox paniculata) and obedient plants (Physostegia) to control height and stagger bloom times.
o Thin tall garden phlox (Phlox paniculata), bee balm (Monarda didyma) and other powdery mildew susceptible plants when the stems are 8” tall to increase air circulation through the stems and decrease mildew risk.
o Plant canna, dahlias, tuberous begonias and caladiums.
o Plant amaryllis bulbs outside in the garden for the summer and continue watering and feeding.
Sources:
Minnich, Jerry. The Wisconsin Garden Guide – The Complete Guide to Vegetables, Flowers, Herbs, Fruit, & Nuts, Lawn & Landscaping, Indoor Gardening. 3rd ed. Madison: Prairie Oak, 1995. Print.
Myers, Melinda. Month by Month Gardening in Wisconsin: What to Do Each Month to Have a Beautiful Garden All Year. Franklin: Cool Springs, 2006. Print.
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