Spring Up Your Seattle Garden: What to do in March

Spring is here! It may not feel like it here in the Pacific Northwest, but the official first day of spring occurs after the spring equinox — around the end of the third week of March. As things begin to (slowly) warm up, you can start planting with the warmer seasons in mind and bring your garden back to life. All this is weather dependent of course, but taking smart steps to knock your garden into shape now will sow the seeds for a successful summer — literally and figuratively!


Now is a great time to divide perennials like hostas, daylilies and chrysanthemums. Do it while the air is still cold and moist so they have a chance to establish themselves before summer and warmer days.

Not only does dividing perennials give you new plants for your garden, but it also keeps the perennials healthy and looking good. In general, a perennial should be divided every three to five years. Oregon State University recommends dividing perennials while they are strong and healthy, but before they become too large to manage. If you begin to see issues: it’s time to divide!

To start, dig a trench around the plant. Go wide to minimize root damage, and then dig under the root clump at various points until it comes out of the hole freely.

How you actually divide the plant depends on its root type. OSU has compiled a list of the five different types of roots and how to divide them here. Keep in mind that you want to divide the healthy parts, as each division must grow successfully by itself. Four to six divisions is a good number, and remember that each section can more than triple in size each season.

Replant the cuttings in holes wide enough to spread out the roots. OSU recommends making a small mound in the hole to spread the roots over. Replant quickly so the divisions don’t dry out, and water them well once planted. Not only have you just saved money, but you’ve also made your garden that much healthier! 


As things (hopefully) warm up later in the month, you can start putting more things in the ground. Early cool-weather crops like peas, carrots, radishes, beets, onion starts and salad greens are good to go. You can also start planting some summer bulbs towards the end of the month.

March weather in the Pacific Northwest can be complicated. One trick is to use a soil thermometer to check your garden regularly. When the ground is consistently above 40 degrees Fahrenheit, and not too wet, you’re good to go.

Now is a good time to mulch and add compost to your soil. If you had your soil tested this winter, you can start making changes to improve the nutrient balance in it. You can also add plants that will attract good insects to help maintain the health of your garden, such as alyssum, phacelia or dill.


As greenery starts to come out of hibernation, it’s a good time to get a head start on taking care of your lawn. You can aerate your lawn while it’s still moist and add seeds to bare spots after scratching the soil. If the lawn is over three inches tall, you can get the mower out on a nice day and give it a trim.

If your lawn has been heavily damaged by winter weather, give us a call to talk about adding in new pieces of sod. We can be reached at 206-551-9872. If all that maintenance sounds like a lot of work, we can also give you options for replacing your lawn with more natural landscapes that use native plants for simple but elegant results.