The fourth week in May is when the soil has warmed and it is time to seed cucumbers, squash, carrots, and other warm season crops directly into the soil. You can also plant seeds of flowering plants such as nasturtiums, sunflowers, marigolds, cosmos and iberis now for flowers that will be blooming this summer.

If you haven’t edged the lawn then set some boundaries now and sharpen the blades of your mower for a crisp, clean cut all summer. Roses, perennials and potted plants need fertilizing this week but don’t go flinging fertilizer around rhododendrons, camellias, azaleas and most other blooming shrubs. Trees and shrubs do fine without additional plant food and too much fertilizer can encourage soft new growth that is weak and attractive to disease and insects – just like over-feeding humans can make them less healthy. Use a compost or organic mulch around trees and shrubs or a slow release plant food.

You can continue to add new trees, shrubs, perennials and annuals to the garden making sure you soak the root ball of new plants before you remove them from the pot and add them to the planting hole.

If you haven’t pruned your roses and they are budded up or blooming, enjoy the flowers in June but then cut back the longest canes after the first flowers fade. You can always remove anything dead, diseased or damaged from a plant no matter the season.

Q. My lilac is done blooming. Do I have to prune off the faded flowers? Also the leaves are curling with some silky threads. Help! D.F., Renton

A. You can get snippy with the faded blooms of lilacs to promote new growth and better blooming. Lilacs also need to have their suckers or new growth coming from below ground removed to keep them from reverting back to wild plants. Shorten the longest branches of your lilac by at least a third to encourage new growth. The curling leaves and silky webs are from banded leaf roller insect. If you have just a few leaves infected, remove them immediately and squish the little caterpillar hidden inside the rolled leaf. If more than a third of the shrub is infected you can spray with an organic spray called BT or Bacillus thuringiensis two or three times over the next few weeks to kill off the worms before they mature into moths. Clean up fallen leaves and debris around your lilac especially in the fall to keep this insect from hiding out in the root zone.

Q. I have a spirea “Magic Carpet” variety growing in a large container. It does very well and blooms most of the summer. My question is how long can this shrub grow in a pot? S.D., Olympia

A. You don’t need to contain your enthusiasm for this happy shrub because potted spiraes have bloomed happily in containers on my patio for almost a decade. Like Japanese maples, they seem to adjust to the potted lifestyle but unlike Japanese maples, spiraes look better when pruned back hard early in the spring. I have found that all the dwarf or compact varieties of spirea do well in containers including the spirea ’Limemound’ the ‘Golden Sunrise’ the ‘Goldflame’ and the beautiful and carefree spirea ‘Magic Carpet.’

Q. What shrubs will do well in the shade? I have some large trees in my back yard and very little full sun. C.C., Maple Valley

A. Filtered shade from tall trees is perfect for growing rhododendrons, azaleas, hydrangeas, leucothe, viburnums, euonymous, yews, even blueberries and nandina along with hundreds of other native and new plant introductions. The important thing is to improve your soil by adding organic matter and mulch the shrubs so that they don’t dry out. All new trees and shrubs will need water the first few summers that they are in the ground. My personal favorite for summer color in the shade is the hydrangea. There are now so many new hydrangeas available that creating an outdoor room using hydrangeas that rebloom such as the “Endless Summer” and “Blushing Bride” varieties is very rewarding. There are also some new dwarf hydrangeas that are perfect for pots on a shaded porch or patio. You’ll pay more for a patented new hydrangea but these hardy shrubs are long-lived and carefree – you’ll have it made in the shade.