March Gardening Tips and To-Dos for the Pacific Northwest Region

We’re finally starting to see colorful blooms in the garden as spring approaches. Here are some March gardening tips and things to work on in your Pacific Northwest garden.

Bulbs are finally popping out of the ground. Hellebores and camellias are in full bloom. It’s finally beginning to feel like spring is not that far away.

This is the time when I am back in the greenhouse full time and loving every minute of it.

There is plenty of inspiration in the March garden. So many changes are starting to happen here in the Pacific Northwest. The cold wet days of winter are still around, but the amount of daylight is increasing each day which means we can start spending more time in the garden. Daffodils, crocus, snowdrops, and irises are in bloom.

Here are some March gardening tips and things to do to get your garden ready for the next growing season.

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Garden Planting and Sowing Seeds in March

Vegetables to Plant in the Ground

Cool-weather crops | broccoli, Brussels sprouts, cabbage, cauliflower, kale, onions and shallots can be directly planted in the garden as soon as the soil temps are consistently at or above 40°F.
Root vegetables | beets, carrots, radishes
Bare-root | asparagus and rhubarb
Leafy | spinach and lettuce
onions and shallots

Planting Asparagus

When planting crowns in early spring as soon as the soil can be worked, you should have asparagus to eat the following year. It can take 2-3 years before you have a harvest if you are planting seeds.

Sow Vegetable Seeds

Cole Crops | Start seeds for cole crops like cabbage and broccoli indoors or directly outdoors.

Warm-season vegetables | Start seeds indoors for basil, eggplant, peppers, tomatoes, cucumbers, and melons.

Sow seeds for peas, artichokes, strawberries, and blueberries.

Start Planting Spring-Planted Bulbs

Start planting spring-planted bulbs such as gladiolus, begonias, ranunculus, and calla lilies towards the end of March.

Sow Flower Seeds

Summer cut flower seeds such as zinnias and cosmos should be sown indoors this month. For more tips on sowing seeds, visit my blog post Seed Starting Basics.

Plant Flowers to Bring Color to the Garden

Primroses, violas, and pansies can be planted around the garden and in containers to brighten up the yard.

Pruning and Cutting Back in the March Garden

Cut Back Old Perennial Growth

Finish Pruning Projects

Fruit trees and grapevines | If you haven’t finished pruning your fruit trees and grapevines already, you’ll want to do so as soon as possible.

Roses | Early in the month, remove old, thin, and unproductive rose canes. Cut back bush roses to 12-18 inches tall and shrub roses to 3 feet.

Group 3 clematis | Italian clematis and scarlet clematis should be cut back in late winter to a pair or two of buds, approximately 8-12 inches from the ground. This group is new wood and should be at eye level when they bloom in the summer.

*Wait to prune spring-flowering shrubs until after the blossoms fade.

Start Removing Winter Mulch

Gradually pull winter mulch from your garden beds as you see plants showing signs of new growth. Acclimate your plants by removing the mulch over a period of several days.

Fertilize Plants and Bulbs

Rhododendrons, azaleas, and camellias | Choose a fertilizer designed for acid-loving plants.

Clematis | Work the fertilizer into the soil around the base of clematis vines and water. Refresh mulch around vines.

Bulbs | As new shoots appear, work in bulb fertilizer into the soil around plants. This feeding ensures an even better performance next year.

Roses | Feed your roses after pruning.

Dividing Summer and Fall Blooming Perennials

Early spring is a good time to divide and transplant crowded and overgrown perennial clumps of summer and fall blooming perennials such as…

Shasta daisies
Black-eyed Susans
Asters
Coneflowers
Garden mums
Day Lilies
Phlox
Sedum Autumn Joy

This timing gives new transplants a full growing season to recover before facing cold winter conditions.

If the perennial blooms before mid-June, then divide in fall. If the perennial blooms after mid-June, then divide in early spring. You can see more information about dividing HERE.

Weed and Pest Control

Stay on Top of the Weeds

It only takes a little sun before the weeds in your March garden start sprouting. Keep up on weeds in garden beds before they grow out of control. Now is the time to weed your garden, before weeds have a chance to flower, and go to seed.

Slug Maintenance

Rain brings slugs and snails, so control them by eliminating their hiding places. Clean up leaves, and use some slug bait around your most susceptible plants.

Apply Deer Repellent

The deer love tulips. When you start to see tulip foliage pop up out of the ground make sure you spray a deer repellant when you have a day that has no rain or wind.