Month by Month Gardening Tips
May
May 10 is our frost-free date. Annual flowers and vegetable plants can be set out now.
Sow seeds of beans, beets, and carrots.
Garden centers and nurseries have the best selection of perennials and groundcovers at this time of year. This is an excellent time of year to plant them.
May is still okay to dig and divide perennials that have already bloomed.
When spring bulbs have finished blooming, have died back and are yellow, bulb tone can be applied. Do not cut green foliage, let it die back.
This is a good time to prune spring flowering shrubs that have finished blooming.
Tender bulbs can go in the ground once the danger of frost has passed.
May is mulch month but do not over do it. Use no more than 3 inches around trees and shrubs. 2 inches is more than enough around perennials.
Houseplants can be put outside. Harden them off by bringing them in each night for a week.
When watering roses, water the soil around them. Damp leaves are more prone to blackspot and other disease problems.
Annuals in pots and baskets require more fertilizer than in-ground plants since nutrients drain out with frequent watering.
You are likely to see ants swarming over your peony buds. They do not harm the plants. They are simply interested in the sugars the buds are secreting.
Hummingbird feeders should be out now. Change the sugar water every 3-4 days.
Keep birdbaths clean and filled with water.
Be sure trellises are installed several inches from walls to allow air circulation.
Paint tool handles with a bright color so you can find them in the grass.
Sow seeds of beans, beets, and carrots.
Garden centers and nurseries have the best selection of perennials and groundcovers at this time of year. This is an excellent time of year to plant them.
May is still okay to dig and divide perennials that have already bloomed.
When spring bulbs have finished blooming, have died back and are yellow, bulb tone can be applied. Do not cut green foliage, let it die back.
This is a good time to prune spring flowering shrubs that have finished blooming.
Tender bulbs can go in the ground once the danger of frost has passed.
May is mulch month but do not over do it. Use no more than 3 inches around trees and shrubs. 2 inches is more than enough around perennials.
Houseplants can be put outside. Harden them off by bringing them in each night for a week.
When watering roses, water the soil around them. Damp leaves are more prone to blackspot and other disease problems.
Annuals in pots and baskets require more fertilizer than in-ground plants since nutrients drain out with frequent watering.
You are likely to see ants swarming over your peony buds. They do not harm the plants. They are simply interested in the sugars the buds are secreting.
Hummingbird feeders should be out now. Change the sugar water every 3-4 days.
Keep birdbaths clean and filled with water.
Be sure trellises are installed several inches from walls to allow air circulation.
Paint tool handles with a bright color so you can find them in the grass.
Native flowers in bloom
Black Raspberry, Black Locust, Eastern Red Columbine, Common Cinquefill, Northern StarFlower, Common Strawberry, Fleabane, Foamflower, Pink Lady's Slipper, Mayapple, Painted Trillium, Common Pawpaw, Wood Geranium, Wood Anemone, Jack-in-the-Pulpit, Ramps, Sessile Bellwort, Golden Ragwort. Wild Blue Phlox
Black Raspberry, Black Locust, Eastern Red Columbine, Common Cinquefill, Northern StarFlower, Common Strawberry, Fleabane, Foamflower, Pink Lady's Slipper, Mayapple, Painted Trillium, Common Pawpaw, Wood Geranium, Wood Anemone, Jack-in-the-Pulpit, Ramps, Sessile Bellwort, Golden Ragwort. Wild Blue Phlox
Perennials in bloom
Alliums, Ajuga, Dianthus, Fringe leaf bleeding hearts, Amsonia, Baptisia, Brunnera, Catmint, Chives, Geranium, Jacobs ladder, Lamium, Lily of the Valley, Iris, peony, salvia, Sweet Woodruff, Solomons seal, Honeysuckle, Kousa Dogwood
Alliums, Ajuga, Dianthus, Fringe leaf bleeding hearts, Amsonia, Baptisia, Brunnera, Catmint, Chives, Geranium, Jacobs ladder, Lamium, Lily of the Valley, Iris, peony, salvia, Sweet Woodruff, Solomons seal, Honeysuckle, Kousa Dogwood
June
To attract butterflies, include both host plants, where they lay their eggs and nectar plants to provide food for the adults. Good host plants: dill, parsley, marigold, snapdragon, turtlehead, milkweed and clover. Host plants: cosmos, pentas, salvia, catmint, coreopsis, goldenrod, joe pye weed, mountain mint, and bee balm.
When planting new plants do so on cloudy days and keep them well watered over the next 4 to 6 weeks and especially dry times during the remainder of the summer.
Pick weeds when they are young as you do not want them to steal sunlight, nutrition and water from other plants.
Deadhead faded blooms. This neatens the plant, encourages continuing blooms and sometimes lessens the odds of mildew disease.
Some annual flowers such as zinnias, cosmos and larkspur may require stakes later in the season. Stake them now.
Newly planted perennials are still establishing their root systems. Be sure to give them a good soaking once or twice a week.
Potted plants and vines often require a daily soaking until the water drains out of the bottom.
Perennials in pots benefit from more nutrition as the frequent watering leaches nutrients out of the bottom with the drainage.
Pest insects arrive in the garden before beneficial ones.
Be aware! Black flies, often called "gnats" can get exceedingly annoying this month.
Watch for slugs, especially in shady parts of your yard. They chew leaves (usually at night) and leave behind shiny trails of dried slime.
Look for leaf miner activity. These bugs feed between the upper and lower surface of the leaves leaving tunnels through the foliage. Clip off infested leaves and give the plants a good watering. The will push out new foliage.
When planting new plants do so on cloudy days and keep them well watered over the next 4 to 6 weeks and especially dry times during the remainder of the summer.
Pick weeds when they are young as you do not want them to steal sunlight, nutrition and water from other plants.
Deadhead faded blooms. This neatens the plant, encourages continuing blooms and sometimes lessens the odds of mildew disease.
Some annual flowers such as zinnias, cosmos and larkspur may require stakes later in the season. Stake them now.
Newly planted perennials are still establishing their root systems. Be sure to give them a good soaking once or twice a week.
Potted plants and vines often require a daily soaking until the water drains out of the bottom.
Perennials in pots benefit from more nutrition as the frequent watering leaches nutrients out of the bottom with the drainage.
Pest insects arrive in the garden before beneficial ones.
Be aware! Black flies, often called "gnats" can get exceedingly annoying this month.
Watch for slugs, especially in shady parts of your yard. They chew leaves (usually at night) and leave behind shiny trails of dried slime.
Look for leaf miner activity. These bugs feed between the upper and lower surface of the leaves leaving tunnels through the foliage. Clip off infested leaves and give the plants a good watering. The will push out new foliage.
Perennials in bloom
Astilbe, bellflower, black eyed susan, cannas, carnations, catmint, coralbells, coreopsis, daylily, delphinium, echinacea, evening primrose, filipendula, foxglove, gaillardia, hardy geranium, hosta, hydrangea, knautia, lady’s mantle, lamium, lupine, penstemon, red hot poker, rodgersia, roses, rose mallow, scabiosa, shasta daisy, spiderwort, tiger lily, verbascum, veronica, yarrow, yucca.
Astilbe, bellflower, black eyed susan, cannas, carnations, catmint, coralbells, coreopsis, daylily, delphinium, echinacea, evening primrose, filipendula, foxglove, gaillardia, hardy geranium, hosta, hydrangea, knautia, lady’s mantle, lamium, lupine, penstemon, red hot poker, rodgersia, roses, rose mallow, scabiosa, shasta daisy, spiderwort, tiger lily, verbascum, veronica, yarrow, yucca.
July
It is time to enjoy your garden.
Harvest annuals and perennials for use in a vase.
Pinch spent flowers.
Annuals can be clipped if they are getting too long
or leggy.
Stake tall plants that are flopping.
High priority watering is needed for newly planted
perennials, shrubs, or trees.
Monitor your garden for pests.
Weed as necessary.
Prune wisteria if you did not do it in June. Thin out
excess branches. Cut back side shoots to 6”.
Do not fertilize a plant under stress from drought or
extreme heat.
Harvest annuals and perennials for use in a vase.
Pinch spent flowers.
Annuals can be clipped if they are getting too long
or leggy.
Stake tall plants that are flopping.
High priority watering is needed for newly planted
perennials, shrubs, or trees.
Monitor your garden for pests.
Weed as necessary.
Prune wisteria if you did not do it in June. Thin out
excess branches. Cut back side shoots to 6”.
Do not fertilize a plant under stress from drought or
extreme heat.
Perennials in bloom:
agastache, lilies, bee balm, black eyed susan, coreopsis, butterfly weed, gaillardia, lavender, hollyhock, hosta, obedient plant, russian sage, sea holly, shasta daisy, echinacea
agastache, lilies, bee balm, black eyed susan, coreopsis, butterfly weed, gaillardia, lavender, hollyhock, hosta, obedient plant, russian sage, sea holly, shasta daisy, echinacea
August
Continue gathering and creating cut flower bouquets including plumes and seed heads from ornamental grass.
Harvest and preserve summer vegetables.
Vegetables that can be planted now include: leafy greens such as lettuce, spinach, collards, kale and mustard.
Radishes, turnips, beets and carrot seeds can be started this month.
No need to fertilize at this time of year. The only exception is potted plants.
1st year perennials may need extra soakings this month.
It is too early and too hot to plant spring flowering bulbs. You can shop now and keep them in a dry and cool area until late September-October.
Continue weeding to prevent seeds from maturing. Weeds are also competing for moisture.
Mulch if you are down to bare soil. This can discourage new weeds, and it keeps the soil cooler.
Use caution with a weed trimmer as they can cause harm to the soft wood of young trees. An injury to the tree allows pests and disease into the tissues.
Cut back leggy stems after they bloom. Continue to deadhead or leave the seedheads for the birds.
Enjoy your garden’s bounty!
Perennials in Bloom:
Aster, Cardinal flower, Goldenrod, Joe Pye weed, Leadwort, Ligularia, Liriope, Monkshood, perennial sunflower, purple coneflower, Russian sage, Sedum, Turtlehead
September
Watch for deals on new plants. Some garden centers have Fall sales. Soil temperatures are warm enough to support good root growth. New plantings lose less moisture in fall than in summer months. Continue to water if there is not much rain.
Dig and divide perennials that are spreading. Perennials that are blooming now are best divided in early spring.
Continue to water potted plants and hanging baskets.
This is the beginning of spring bulb planting. Check bulbs for firmness and plumpness.
Soak the soil right after planting to settle the soil.
Continue to weed. Yes, we need to keep digging and pulling those weeds.
Leave some seed heads on the perennials to provide food for wildlife during fall and winter seasons.
This is a good time to plant evergreens.
Bring in houseplants.
Begin poinsettia treatment for 40 days starting on September 20th.
Plant mums, pansies and other cool weather plants.
Harvest and preserve vegetables.
Dig and divide perennials that are spreading. Perennials that are blooming now are best divided in early spring.
Continue to water potted plants and hanging baskets.
This is the beginning of spring bulb planting. Check bulbs for firmness and plumpness.
Soak the soil right after planting to settle the soil.
Continue to weed. Yes, we need to keep digging and pulling those weeds.
Leave some seed heads on the perennials to provide food for wildlife during fall and winter seasons.
This is a good time to plant evergreens.
Bring in houseplants.
Begin poinsettia treatment for 40 days starting on September 20th.
Plant mums, pansies and other cool weather plants.
Harvest and preserve vegetables.
Plants in bloom:
Aster, catmint, gaillardia, goldenrod, Japanese anemone, Mums, Salvia, Sedum, Toad lily, Turtlehead
Aster, catmint, gaillardia, goldenrod, Japanese anemone, Mums, Salvia, Sedum, Toad lily, Turtlehead
ie
October
It is time to prepare your gardens for cold weather. Bring tropical plants inside. Take cuttings from tender plants before the frost arrives.
Do not cut back perennials if they are still green.
Plant garlic.
This is prime time for planting spring flowering bulbs. These are some species with varying bloom times.
January and February: snowdrops, winter aconite, early crocus
March: spring snowflakes, many crocuses, early daffodils, early tulips
April: glory-of-the-snow, Siberian squill, Grecian windflower, most daffodils, striped squill, hyacinth, mid-season tulips, grape hyacinth, spring starflower
May: Spanish bluebells, camassia, crown imperial, most fritillary, late tulips and daffodils
June: alliums
Newly planted fall plants need at least six weeks of root growth before soil temperature drops below 40 degrees.
This is a good time to prepare new beds for planting in the spring. It is also a good time to mulch.
Seeds of most plants are mature by now. Have fun collecting and do not forget to label. Some easy seeds to collect: marigold, zinnia, larkspur, cosmos, ageratum, browallia, celosia, impatients, nicotiana, petunia, portulaca, salvia, snapdragon, sunflower, gloriosa daisy, ornamental peppers
You can deal with poison ivy now, before birds carry the berries away and start more plants. Use a plastic bag on your hand, pull the plant and dispose of that itch and pain producing plant.
Ornamental grasses can be cut down when
they turn brown, or you can enjoy them for winter
interest.
Enjoy the Fall foliage.
Plants in Bloom: aster, goldenrod, mums, Nippon and Montauk daisy
October
It is time to prepare your gardens for cold weather. Bring tropical plants inside. Take cuttings from tender plants before the frost arrives.
Do not cut back perennials if they are still green.
Plant garlic.
This is prime time for planting spring flowering bulbs. These are some species with varying bloom times.
January and February: snowdrops, winter aconite, early crocus
March: spring snowflakes, many crocuses, early daffodils, early tulips
April: glory-of-the-snow, Siberian squill, Grecian windflower, most daffodils, striped squill, hyacinth, mid-season tulips, grape hyacinth, spring starflower
May: Spanish bluebells, camassia, crown imperial, most fritillary, late tulips and daffodils
June: alliums
Newly planted fall plants need at least six weeks of root growth before soil temperature drops below 40 degrees.
This is a good time to prepare new beds for planting in the spring. It is also a good time to mulch.
Seeds of most plants are mature by now. Have fun collecting and do not forget to label. Some easy seeds to collect: marigold, zinnia, larkspur, cosmos, ageratum, browallia, celosia, impatients, nicotiana, petunia, portulaca, salvia, snapdragon, sunflower, gloriosa daisy, ornamental peppers
You can deal with poison ivy now, before birds carry the berries away and start more plants. Use a plastic bag on your hand, pull the plant and dispose of that itch and pain producing plant.
Ornamental grasses can be cut down when
they turn brown, or you can enjoy them for winter
interest.
Enjoy the Fall foliage.
Plants in Bloom: aster, goldenrod, mums, Nippon and Montauk daisy
Planting Depths for Bulbs
November
‘Tis the season for some frosty nights which puts many perennials into winter dormancy.
Some perennials hold their foliage all year long. Some of these include:
vinca, pachysandra, ivy, hellebores, foamflowers, some ferns and creeping sedums
If the fall season has been a dry one, you may want to give a good soaking to anything you planted this year.
November is a good time to add a light coating of compost to your gardens.
Outdoor roses do not need fertilizer at this time of year. November is a good time to apply manure, before the ground freezes
Dig, clean, dry and store tender bulbs such as dahlias, cannas, callas, gladioli and elephant ears.
Protect spring bulbs from being pushed up by freezing and thawing of your soil. Add 2 inches of chopped leaves or bark mulch.
You can pot up any bulbs you did not get into the ground using a winterized container.
Amaryllis and paperwhites will root and bloom without a chill period.
Hyacinths that have been prechilled can be forced for indoor bloom, using a bulb vase.
Plants in bloom:
Aster, Boltonia, flowering cabbage and kale
Some perennials hold their foliage all year long. Some of these include:
vinca, pachysandra, ivy, hellebores, foamflowers, some ferns and creeping sedums
If the fall season has been a dry one, you may want to give a good soaking to anything you planted this year.
November is a good time to add a light coating of compost to your gardens.
Outdoor roses do not need fertilizer at this time of year. November is a good time to apply manure, before the ground freezes
Dig, clean, dry and store tender bulbs such as dahlias, cannas, callas, gladioli and elephant ears.
Protect spring bulbs from being pushed up by freezing and thawing of your soil. Add 2 inches of chopped leaves or bark mulch.
You can pot up any bulbs you did not get into the ground using a winterized container.
Amaryllis and paperwhites will root and bloom without a chill period.
Hyacinths that have been prechilled can be forced for indoor bloom, using a bulb vase.
Plants in bloom:
Aster, Boltonia, flowering cabbage and kale
Sources: Month by Month Gardening in Pennsylvania, Master Gardeners of Mercer County NJ