Time to start movinging your houseplants outside

Houseplants: Move houseplants outside to protected areas once temperatures remain consistently above 40 degrees, even at night. Prevent any damage to the plants by gradually acclimating them to the sun and outside growing conditions. Start by putting them in a shaded location outside on warmer days and bringing them inside when nights are predicted to be cold. Gradually increase the time they spend outside and their exposure to sun over a period of 10 days or so.

Large houseplants in plastic pots should be slipped into larger, heavier pots to keep the wind from blowing them over.

Seasonal plantings: Containers for seasonal plantings should have at least one bottom hole to allow water to drain away. Fill the container with a lightweight, fast-draining soilless potting mix; do not use heavy garden soil. Leave enough space below the rim of the pot, so that water can pool and soak in when you water.

A layer of gravel in the bottom of a container is not necessary and does not improve drainage. However, you may save potting mix in a very large container by partially filling it with wood chips or empty plastic pots. Separate the wood chips from the growing mix with porous landscape fabric. Most annual flowers need only 8 to 10 inches of soil depth.

Shrubs and hedges: Some of your shrubs may have grown unevenly. Prune back any errant branches to even out the shrub and encourage it to fill in more evenly. You also can gently prune back the new growth to encourage the development of a fuller plant.

Lightly shear your formal hedges to neaten them up and train their shape. These hedges will likely continue growing through the season and need to be pruned again in July.

• Tim Johnson is director of horticulture at Chicago Botanic Garden, chicagobotanic.org.