Fluctuating temperatures make spring a challenge

You never know what to expect with this fluctuating early spring weather — and how your plants might be affected, just as they start to emerge.

The warm weather means that some crabapples are starting to leaf out earlier than in typical springs. I’d recommend spraying these crabapples if they are susceptible to a fungus called apple scab (typically this disease affects older varieties of crabapples). If your tree’s leaves become covered with black spots and fall off in late summer, consider using a protective spray program or replacing the plant with a new disease-resistant cultivar.

After the buds open, I’d begin spraying and treating once every seven to 10 days until the leaves are fully open (generally, three treatments should work). If you need information on recommended fungicides and timing for applications, call the Chicago Botanic Garden’s Plant Information Service, (847) 835-0972.

• With the unpredictable weather, you might want to think about how to maximize your time. I’d continue to avoid working in beds when the soil is wet, after a late-season snowstorm or rain. Garden soil will take more time to dry out than in the summer after rain events since the weather is cooler in spring. The structure of the soil can be damaged if you dig while the soil is too wet to work. Also, remember to avoid walking too much in wet beds to avoid damaging the soil.

• Spring is a time when big rains are possible. To protect emerging tulips from deer and rabbit damage, I’d reapply repellents after measurable rainstorms. I wear plastic gloves when applying repellents to avoid getting the spray on my skin and bringing the bad smell with me into the house. Spraying tulips as they grow will help protect the new growth — the rate of growth will be determined by weather, with the bulbs developing faster during periods of warm weather. Animals do not usually eat daffodils and ornamental onions.

• Weeds are already up and growing at the Chicago Botanic Garden. Early spring is a good time to get a jump on weeding beds. Star of Bethlehem is an invasive weed with grasslike foliage I found in my home garden and lawn. Use a trowel or dandelion digger to carefully remove the bulbs of this plant and then discard in the trash.

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