For those of you in colder climates who have been gazing longingly at the spring chores popping up in our garden calendar, May is the month for you! Much of the country will experience the last frost of the season sometime this month, bringing with it heady days of spring gardening.
So whether you’re just getting your hands dirty for the first time this year, or already have calluses from digging, here are some tips and chores for your May garden and lawn.
Azaleas put on quite a show this month.
Trees and Shrubs
- Fertilize azaleas, rhododendrons, and camellias after they bloom with a fertilizer made for acid-loving plants.
- Prune spring-flowering trees and shrubs soon after they bloom. Since they begin setting next year's flower buds in late summer, it’s important to have them pruned and fertilized before then.
- Fertilize roses, and keep an eye out for fungus and disease.
- Plant container-grown trees and shrubs. Stop planting bare-root trees and shrubs as soon as they begin to leaf out.
- Transplant trees and shrubs well before hot weather hits, and keep them well watered.
- Prune back any damage from winter.
- Lightly prune evergreens, making sure not to cut back to bare branches.
- Apply mulch to shrubs with shallow roots (such as camellias and azaleas) as protection from summer heat and weeds.
Irises are stunning and very easy to grow.
Perennials and Bulbs
- Pinch back mums and asters to encourage full growth and late-season blooms.
- Allow the foliage from spring bulbs to die back naturally on its own, since cutting it back can risk the health of next year's flower.
- Plant tender bulbs such as caladiums, dahlias, and gladiolus, after your last frost.
- Deadhead perennials and bulbs throughout the blooming season.
- Fertilize bulbs after blooming.
- Plant perennials before the heat of summer.
- For best results, transplant perennials before they are 6” tall, and don't disturb spring-bloomers until fall.
- Install stakes and supports for large perennials before they need it.
- Train vines to grow up trellises and fences.
- Clematis vines like cool roots, so apply mulch or plant a low-growing ground cover to shade the ground.
Plant summer flowers after the last frost.
Annuals and Containers
- As soon as the last frost has passed, plant heat-loving summer annuals such as marigold, cosmos, and zinnia.
- Deadhead annuals throughout the season.
- Pinch back any leggy growth to encourage bushy plants.
- Many summer-blooming tropical plants (such as hibiscus and mandevilla) bloom on new growth. Fertilize (and prune carefully) to encourage more growth and flowers.
- Be sure to use fresh potting soil in your containers – old soil has fewer nutrients and may contain harmful bacteria and fungi.
Keep your lawn watered, especially if you applied fertilizer.
- Fertilize warm-season grasses (such as St. Augustine, zoysia, Bermuda, and centipede). Stop fertilizing cool-season grasses (such as fescue and bluegrass) to prevent heat damage.
- Mowing season has begun! Set mower blades at 2”- 3” or higher for cool-season grasses. Warm-season grasses can be cut lower. Mow often and don't cut more than half the blade at a time.
- Apply post-emergent weed control products to broadleaf weeds.
I keep rosemary by the kitchen door for cooking.
Vegetables and Herbs
- Enjoy cool-season vegetables (such as spinach, carrots, and lettuce) before hot weather brings an end to the harvest.
- Plant warm-season vegetables (such as tomatoes, peppers, and corn) after the last frost.
- Plant successive crops of veggies every few weeks to extend your harvest.
- Control weeds to reduce competition for water and nutrients.
- Enjoy strawberry season while it lasts!
- Address insect and disease problems as soon as you spot them.
- Keep up with the harvest to encourage your plants to continue producing.
- Don't apply sprays to plants that are blooming or fruiting.
Houseplants will begin their spring growing season this month.
- Once nighttime temperatures are above 50° F, put your houseplants outdoors on a shady porch so they can enjoy the summer heat while protected from strong sun and wind.
- You can also bury potted houseplants up to the rim in planting beds to add texture.
- Repot root bound houseplants.
- If not repotting, remove the top inch of soil and replace it with fresh compost.
Nesting houses are an easy way to ensure hours of bird watching.
Cleanup and Maintenance
- Make sure that lawns and gardens receive an inch of water per week. Hand water new transplants until they become established.
- Turn your compost pile regularly.
- Get ready for bird nesting season!
- Feed the hummingbirds.
- Apply mulch under plants to keep the soil cool this summer.
- Be on the lookout for lace bugs and aphids this month.
- Examine conifers for the egg sacs of bagworms and remove before the eggs hatch.
- Take photos of blooming plants you enjoy, so you'll know what to buy for your own garden!
- Try something new this year – visit a specialty plant nursery and explore the many varieties of plants available.
- Don't let weeds and vines get out of control – remove (or prune) them while they're manageable.
- Add water lilies to your pond when the water temperature reaches 70° F.
- When you prune, pinch, and trim, try rooting the cuttings to make more plants.