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.
- 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.