Crocuses good for lawns, ideal in rock gardens
Crocuses are ideal bulbs for naturalizing, for rock gardens or for underplanting beneath tall trees. They may be scattered in lawns, but it will affect mowing.
For best long-term results, the bulbs' grasslike foliage must remain intact for at least six weeks before being mowed at a short height. Spring-blooming bulb plants need to keep their leaves after blooming to develop the next year's flowers.
Crocuses, which are planted shallowly, are easy targets for rabbits and squirrels.
One way to deter animals is to place a light screen of chicken wire directly over the bulbs before covering them with soil. Blood meal sprinkled on the ground after planting also may help repel squirrels and chipmunks.
After a killing frost, remove dead plant debris from annual and vegetable beds. Sanitation is especially important if you have had disease problems in your planting beds. Remove all diseased foliage or fruits.
Do not add the affected materials to your compost pile, since most home compost piles do not get hot enough to kill disease organisms.
It is best to stay off the lawn when frost is present. Frost on the grass indicates that water inside the leaves is frozen.
Traffic on the turf can cause the ice crystals inside the plant cells to rupture the cell walls, which kills or severely stunts the leaves.
When frost is very heavy, the cell disruption can occur at the crown and kill the entire plant. The symptoms will generally appear purplish to black in color at first and then progress to a straw color.
If there is no damage to the crowns, the grass plants will recover and grow new leaves as long as the ground has not yet frozen. Once the entire lawn has frozen, walking on the turf is less of an issue.
• Tim Johnson is director of horticulture at Chicago Botanic Garden, chicagobotanic.org.