If they are commonly known as butterfly weed, why are my asclepias covered in aphids? It seems common this time of year to see them congregating on plants in the garden.
The best control is … ignore them. This time of year, their feeding can do little to actually harm or distort plants. Aphids have piercing-sucking mouthparts and usually their feeding distorts the leaf and stem tissue as it is developing.
You will typically see them at the top of plants in the newer softer growth. If it was early in the season and the plants weren’t developed yet it would be effective to blast them off with a garden hose — or my favorite ways is to smash them with a gloved hand. Once they are blasted off they really do not have the ability to crawl back up.
Aphids come in a variety of colors: grey, black, green and, this year, yellow/orange in my garden. Often you will see ants farming the aphids for their honeydew, but a few finger taps on the plant produced no ant protectors, so the aphids are on their own from their main predator, the lady beetle.
The elusive spotted iris ...
A few questions at the Farmer’s Market this week: What are all the spots of my iris leaves? Leaf spot! This time of year, the iris plants can get ugly looking with leaf spot and browning of the leaves.
Feel free to cut them back, leaving 6-10 inches of growth, and start to clean them up by removing any dead leaf material for fall.
You will see a flush of new green growth and will have to cut them back again after a hard frost, or early in the spring. If you are dividing or moving irises, that process should stop by mid-August.
Otherwise the plants may not have enough time to establish themselves with root growth to survive winter.
A rose by any other name
I also had a question about fertilizing rose plants.
Roses are heavy feeders and fertilizing is usually necessary for optimum results. Fertilize early in the season when roses are in their rapid growth stage. Fertilizing should stop by the end of July or early August as the plants will begin preparing for winter.
Fertilizing will create new soft growth late in the season when the plant needs to be hardening off. Choose a fertilizer with the middle number of the analysis higher, like a 10-20-10, or 5-10-5.
As blooms fade, prune off the remaining flower head before the rose hip develops. The plants use a large amount of energy to develop the hips that could be better used developing more flowers!
Another question was about plants that are good for partial sun.
The first thing to consider is when is the sun/shade present?
Plants that are considered “full sun” need 6 hours of sun between 9 a.m. and 6 p.m. every day. If your area is shady in the morning and evening, then full-sun plants should be fine. If your area is shady during these hours or there about, then shady plants should work for you.
Daylilies of course come to mind as not too fussy and durable anywhere. Others that will perform in full sun or part shade are: Echinacea’s, Baptisia (false Indigo), Dianthus, perennial geranium, Monarda (bee balm), Heuchera (coral bells), Heucherella (foam flower), Siberian iris and peony.
Be mindful that your sun/shade can change over the years as trees and shrubs grow and throw more shade … or you cut a tree down!
Which brings me to a final point of a personal recommendation I have been making over the years that I need to retract.
Autumn blaze is ... the worst!
After cutting down another Autumn Blaze Maple due to wind damage, I am done with them. Three of my six have had substantial damage from storms over the past years, when all the other yard trees have withstood it!
Autumn Blaze (Acer fremanii), is a hybrid tree that is produced under cultivation. It is a cross of the slower-growing red maple and the faster-growing silver maple, resulting in a faster-growing tree with stunning fall color. Trees that have a fast growth rate typically do not have as dense a cell structure as slower-growing trees, allowing for easier breakage.
Autumn Blaze is not the only Acer hybrid, but it certainly was very popular the last 20 years. Done with it!
The Mankato Farmers’ Market is now open for 2019, 8 a.m. to noon Saturdays in the Best Buy parking lot in Mankato. The Tuesday market is held 3:30-6 p.m. at Best Buy. The Thursday market will be held 3:30-6 p.m. at the Food Hub in Old Town, 512 N. Riverfront Drive.