Midsummer Maintenance in the Rose Garden

By Diane Brueckman

(This article was first published in The Gateway Gardener July 2009 issue.)

If you haven’t already done so give your roses a second feeding. I like to do the organic fertilizers such as my Chicken Soup. If you use a chemical fertilizer like 12-12-12 give the roses 1/2 cup to 1 cup depending on the size of the bush. Whichever fertilizer you use, you can add 1 or 2 tablespoons of epsom salts. Try not to get epsom salts on the foliage or too close to the bud union, any fertilizer has the potential to burn. Chemical fertilizers are most likely to burn the foliage. If the temperatures are below 90 degrees, think about giving your plants a liquid feed. Monty’s Plant Food is excellent but fish emulsion or a sea kelp mixture is also very good. I have used a liquid bloom booster fertilizer with success in the past. I apply any liquid feedings at half the recommended rate.

After the once-blooming roses (Old Garden Roses or Species Roses) have finished blooming it is time to give them their annual haircut. If your Old Garden Roses and Species Roses have only been in the ground for a year or two, be gentle with the pruners. Take out only damaged or dead canes. However, if they are established, you will want to be more aggressive with your pruning. Take out the oldest canes or the canes that did not bloom as much. I usually take them out from the bottom of the bush. Next trim the longest canes down about 1/3 of their length. In total try not to remove more than 1/3 of the plant’s mass. Repeat-blooming OGRs can be deadheaded to encourage more bloom.

For the best bloom on modern roses, it is important to deadhead. Cut the spent blooms down to a five-leaflet leaf, preferably one that points away from the center of the plant. The cut should be 1/4 inch above the leaf. You should also leave at least 2 five-leaflet leaves on the cane that you are cutting. To keep on blooming your climbers will need some deadheading. It is almost impossible to completely deadhead a vigorous climber but you can do enough to keep the plant neat and blooming. If the lateral shoots have become too long and are getting in the way of passers by cut them back to about four leaves or tie them to the support.

It is important that you keep up with spraying. However, if the temperatures are in the 90s, it is best to wait for a cooler day. At any temperature, spray early in the morning or in the evening to prevent damage to the plants. Be sure the plants are well watered before you spray.

Insect control (Japanese beetles) is always a challenge. Unfortunately, I have no new Japanese beetle control ideas – the usual grub control, beetle traps, hand picking them into oily water and spraying them with Sevin. Pardon me, I do have a new beetle trap: carnivorous plants, in particular the pitcher plant. I’ll let you know if they catch any.

Diane Brueckman is a retired rosarian with Missouri Botanical Garden, and currently owns Rosey Acres in Baldwin, Illinois. You can reach her at (618) 785-3011.