Are your peonies suffering from blight?

Q. My peonies suffered from Botrytis Blight last year. What is the best way to care for them to keep the fungus away this year?

A. As you may know from your past experience, diseases can affect flowering. Botrytis Blight occurs during cool, rainy spring weather. The young buds can blacken and die or they don't open or open partially. It can also infect and spot blooms in the later stages of development. After the bud infection it can move to the stem and then onto the roots, causing the whole stem to die.

If you see the stem dying from the top down, promptly cut them out making sure cuts are well below the diseased area. If the entire stem appears dead, pull it from the base. If the foliage is dead, remove it from the area after it has been cut.

The fungus can overwinter on live or dead plant material. If the problem persists each year, start spraying with an approved fungicide in early spring as leaves begin to emerge and repeat several times, particularly during wet seasons.

Peony plants form next year's flower buds during August and early September. Since hardy growth influences development of flower buds, additional fertilization during this period can be beneficial. Use fertilizers with high phosphorous and potassium levels and low nitrogen analysis. Over-fertilization with high levels of nitrogen can reduce bloom. Materials such as 5-10-10 should be spread 2 to 4 pounds per 100 square feet of bed area. If growth is good or a spring application was used, the addition of only a phosphorous source is sufficient during the bud-forming period.

Plants are more likely to suffer from Botrytis Blight due to poor air circulation and moisture sitting on the plants and not drying off fast enough. Peonies prefer a full sun location. If the vegetation surrounding the peonies has become overgrown, and the peonies aren't getting enough sun, you may need to re-evaluate the location of your plants and transplant them this fall.

- Terri Passolt

Q. I read that you should wait two weeks before you fertilize your newly planted annuals? Why?

A. Annual flowers can be planted in gardens to brighten up the beds while perennials get growing or can be arranged in containers that can be placed strategically for best show. Either way you do it, your plants should be moved from the nursery or homegrown pot to a bed or container that has soil that is optimal for that plant to grow well right from the start.

For garden beds, you should prepare soil for annual plants by amending it with 1 to 2 inches of organic matter, such as compost, and, if necessary, fertilize it with a slow-release product ahead of planting to allow the new transplants' roots to take up the nutrients provided by both. If you use slow-release fertilizer in the soil, the plants should be able to take up what they need at each watering without risk of burning or over-fertilizing. In that situation, you should not need to wait two weeks to fertilize.

If you are planting in containers, you want to use proper container medium for the type of annuals you are planting, which you can buy from a nursery, and use a slow-release fertilizer because that type allows the nutrients to be available each time you water instead of all at once.

Fertilizers come in many different types and methods of delivery. Pay attention to the expected length of time the slow-release type will be available to your plants. You may need to add more of this type of fertilizer later in the season if the product says it lasts three months or less and your growing season from time of planting exceeds this period. Be sure to follow the product instructions and use less if your garden or container planting is smaller than the product gives guidelines for using.

Most nursery purchased transplants should have adequate root systems to prevent fertilizer burn if you follow the guidelines above. It is possible to have homegrown seedlings that are not yet fully ready to transplant that could be burned by a sudden burst of too much fertilizer, but that can be avoided by waiting to transplant until seedlings are ready and planting in amended soil that has slow-release fertilizer added per the package instructions and with the size of the bed or container taken into account.

- Nancy Degnan

• Provided by Master Gardeners through the Master Gardener Answer Desk, Friendship Park Conservatory, Des Plaines, and University of Illinois Extension, North Cook Branch Office, Arlington Heights. Call (847) 298-3502 on Wednesdays or email northcookmg@gmail.com. Visit web.extension.illinois.edu/mg.