Late spring gardening
If you haven’t done it yet, now is a great time to add 2-4” of compost to your garden beds. If you have containers, you should remove about half the old soil and add new potting soil. If you have trees, shrubs, or perennials in containers, remove about 2” of soil from the surface and add fresh soil, mixed with some compost if possible.
You can start planting perennials, trees, and shrubs now.
Trees and shrubs:
Buy your trees and shrubs from a local garden center, and ask where the tree was grown. Plants grown in much warmer climates or with acid soils may not perform well here. Look for the root flare at the base of the trunk of the tree; if you can’t see it, you’re going to need to remove soil until you find it, because you want to plant the tree so that the root flare is just above the soil level. (Think about trees you see in nature; they never look like lamp posts!)
Dig a hole that’s no deeper than the pot the tree comes in, but is 2 times as wide. Do not add compost to the hole, because that encourages the roots to circle the tree instead of growing out. Loosen the soil around the roots, and place the tree so that the root flare shows, filling in the hole with the soil you removed.
Give your new tree extra water for its first season or two. I like to put a hose on top of the roots and let it just drool onto the soil for half an hour, every day for the first 4 weeks, and then every other day after that for the next 8 weeks.
I urge you to plant native trees whenever possible. They are hardy, having evolved to live in our climate. They also provide food to the local bugs that in turn are food for birds. In that way, native trees help to preserve biodiversity in our community, forming a crucial link between managed natural areas, residences, and the birds’ migrations. For a good list of Illinois native trees and shrubs, try these two links: http://www.mortonarb.org/tree-plant-advice/article/859/native-trees-of-the-midwest.html and http://www.mortonarb.org/tree-plant-advice/article/843/salt-tolerant-trees-and-shrubs.html
Again, buy good-quality plants from a garden center, not a big box store. Plants raised in our general area do better, and if you’re planting perennials, you want them to come back year after year.
Be sure you know the plant’s light requirements. Full sun means 6-8 hours a day; part sun means 4-6; shade means fewer than 4 hours, or dappled shade. Check for the plant’s moisture needs as well, and group plants according to their need for watering.
If possible, find native perennials for your home garden. There’s no shortage of beautiful local plants – coneflower, black-eyed susan, bleeding hearts, and lots of others. Here’s a starter list. It’s from Pesche’s garden center, and this doesn’t constitute an endorsement, but they do put together a good list!
Annuals and Vegetables
You can plant tender annuals and veggies after the last frost date, which is usually May 15th. I often use Mother’s Day as a guide.
Make sure you plant vegetables in either a raised bed or a container. Urban soils often contain heavy metals, which can make their way into the food, so if you want to plant on the ground, make or buy a bed that’s at least 6” and preferably 12” high, and lay landscape fabric on the ground before you add organic soil that you purchase at a garden center. Get either cedar or juniper lumber for your bed; the treated lumbers that sometimes are used to make decks have cyanide in them. (I don’t like them for decks for that reason.)
You can start veggies from seed indoors before you plant them out, or you can buy small plants at a garden center to plant directly into your bed. Cool season plants like spinach, lettuce, radishes, and peas can get planted in April. Warm season plants like tomatoes, peppers, melons, beans, and squash like warm soil and won’t really grow until the soil warms up, usually in late May.
Pinch back fall-blooming perennials such as New England Aster and Sedum once a week until mid-July. This promotes a shorter, stockier plant with more flowers.
Let your bulb foliage yellow and wither before you cut it off. This is how the plant creates new tissue for next year’s flowers. You can apply a 5-10-5 or a 10-10-10 fertilizer to the roots of the bulbs now.
Divide perennials when they are 4-6” tall. However, do not divide day lilies (September), Oriental poppies (July), or iris (late July) at this time. Hostas are easy to divide: get a sharp spade and cut the plant in two. Gently dig each half up and replant in a hole you have prepared. Make sure all parts of the original plant get extra water for awhile.
Prune your spring-flowering trees and shrubs once they’ve finished blooming.
Mow your lawn 2-1/2” to 3” high and leave the clippings on the grass for added fertility. If they are heavy and wet, you can rake some of them up, and put them in compost.
Better to fertilize lawns in fall than spring, but if you forgot to do it last fall, do it now. I prefer organic fertilizers and hand weeding: your kids and pets don’t need poisons in their yard, and neither do you!