Chicago Botanic Garden Summer 2019

Ask the experts Do you have a question for our experts in the Plant Information Service? If so, contact them at plantinfo@chicagobotanic.org or call (847) 835-0972 . Q. How far apart should I plant new perennials, and how do I estimate how many plants I need? A. Perennial plant widths are usually listed on the label and represent the mature size of the plant. Decide how far apart you want the plants on center (O.C.). Measure from the center of one plant to the center of the next to determine the plant locations. Perennials with a mature width of 2 feet planted 2 feet O.C. will theoretically not overlap. If you want the plants to overlap, you can select a smaller spacing. For example, select 18 inches O.C. for an approximate 6-inch overlap. Use a “Spacing Multiplier Chart” to estimate the number of plants you need. Planting a 25-square-foot area at 18 inches O.C. requires about 11 plants, using the formula 25 x .44 = 11. Space Between Plants Spacing Multiplier (Plants per square foot) 4" 9 6" 4 12" 1 18" 0.44 Plants are sold in standardized sizes set by the American Nursery and Landscape Association. Look for the pot size that ts your budget. Many perennials in No. 1-gallon pots perform well, but smaller pots can save you money. However, smaller plants may need more pampering and patience. Q. The lawn care plan that I’m using includes an application of fertilizer in midsummer. Do you recommend this? A. e key consideration here is soil moisture and the state of the turf grass. If your lawn is a healthy green and has been receiving at least an inch of water per week from rain- fall and/or irrigation, you may proceed with the fertiliza- tion. If the turf grass has gone dormant (turned tan or brown) from lack of rain, we recommend skipping the fertilizer because a dormant grass plant is incapable of us- ing the fertilizer and it will do no good. If you are con- cerned with skipping the broadleaf weed control that is often included with a summer fertilizer application, we suggest using a spot application of an appropriate herbicide to any weeds that may be present. It is important to follow all label directions when applying fertilizers and herbicides. Plant Information Service is sponsored by Learn more Send your plant questions to plantinfo@chicagobotanic.org or call (847) 835-0972. You may also bring plant samples to the certified University of Illinois Extension Master Gardeners at the Plant Infor- mation Desk in the Regenstein Center. For more tips: chicagobotanic.org/plantinfoservice Sign up for adult education classes on plant care: chicagobotanic. org/education chicagobotanic.org 29