April Gardening Tips for the Pacific Northwest
Spring is here! Savor the warm afternoons by working through this month's gardening to-do list. Don't miss these April gardening tips for the Northwest
Visit nurseries now to discover perennials that can add splashes of bloom to your spring garden. Candytuft, basket-of-gold, primroses, and bleeding heart are just a few. Count on early-flowering perennials to provide reliable color for spring borders.
When Bulbs Fade
As bulbs blossoms die, clip flowering stems as close to the ground as possible. Let leaves die gradually. While they're alive, they're building food reserves to support next year's blooms.
Test Garden Tip: Disguise yellowing bulb foliage with perennials that unfurl leaves as bulbs fade. Choose garden phlox, coreopsis, daylilies, perennial geranium, or anise hyssop.
Stage your own garden show by stuffing containers with forced spring bulbs purchased from supermarkets and garden centers. Mingle columbine or wallflower between bulbs to extend the pot's bloom season. When all flowers fade, tuck any perennial bulbs and the columbine and wallflower into planting beds.
It's the ideal time to sow cool-season crops.
Seeds: radish, peas, carrots
Seedlings: broccoli, Brussels sprouts, cabbage, cauliflower
Test Garden Tip: Make weekly sowing of lettuce and garden green seeds to ensure a long salad harvest season. Plant a variety of lettuces to fill a colorful salad bowl.
It's too early to set seedlings of tomatoes, peppers, and eggplants into the garden, unless you're using frost blankets or another form of frost protection.
Look for seedlings of chives, oregano, parsley, rosemary, and mint. Plant them as soon as soil is workable.
Early spring is the ideal time to get container-grown perennials into the ground. Improve soil as you plant by adding a shovel of compost to each planting hole.
Divide perennials that aren't spring-bloomers. If leaves are already knee-high when you're dividing, cut them back by half. Two perennials you should wait to divide: bearded iris, which is best to divide in late summer, and peonies,which rarely need divided, but the right time is early fall. When do peonies require division? If plants aren't growing well, if you want more plants, or if the planting spot has grown shady.
Strike a blow against weeds by adding a pre-emergent weed killer to planting areas. Apply it in early April for long-lasting results. This type of weed killer interferes with seed germination. Do not use it anywhere you plan to plant seeds or hope self-sowing annuals will sprout.
Test Garden Tip: Watch for aphids on young perennial growth. Blast aphids off growth with a strong spray of water. Aphids aren't nimble enough to assemble and regroup, so you've controlled the immediate problem. Keep a watch on tender shoots for future generations.
Deadheading 101 -- Deadhead rhododendrons and azaleas by cutting or pinching off spent flower trusses. This helps neaten their appearance and encourages future blooms
If wayward or damaged branches detract from an azalea's post-bloom appearance, prune immediately after flowering.
This is also a good time to plant azaleas. If possible, purchase plants in bloom to ensure you're getting the color you want.
Houseplants and Tropical Plants
When night temperatures stay reliably above 50 F, move overwintered houseplants and tropical plants outdoors. Tuck them in a shady spot for the growing season.
Use an all-purpose liquid fertilizer to stimulate fresh growth. Consider replacing the top inch or two of soil with a layer of compost. If you do this, don't apply a separate fertilizer.
Test Garden Tip: Apply slug bait and handpick slugs early in the season to try to control populations before they explode.
In the coldest areas of the region, continue to plant bare-root trees, shrubs, and roses. In lower elevations and coastal zones, focus on planting container-grown nursery stock.
In either area, it's also the right time to plant fruit -- bareroot or container-grown. Look for cane berries, kiwis, grapes, strawberries, and fruit trees.
After all danger of frost is past, plant tender summer bulbs outdoors, including gladiolas, cannas, dahlias, and tuberous begonias.
Test Garden Tip: Get a jump on the growing season by tucking these roots into black nursery pots and sitting them on a sunny patio. Spring sun will warm the pots and soil within, and you'll have happily rooted plants ready for transplanting. Just protect shoots if a freeze is predicted
Prune spring-blooming shrubs after flowers fade. Don't postpone the pruning task too long. Try to prune immediately after flowering so you're not cutting into next year's blossoms.
Finish any other pruning this month, with the exception of evergreens. Prune these any time from now to late summer.