Fielding Questions: Early-fall colors don’t always forecast harsh, early winter
Q: My Autumn Blaze maple leaves are prematurely changing to fall colors. I know if the leaves are very light green, the issue is lack of iron.
I’m worried they will start dropping and there might be an issue with the tree itself. A neighbor’s Autumn Blaze leaves are starting to change, too. I took a soil sample to NDSU last week and am awaiting results. Any ideas?
– Kathi Schwan, West Fargo
A: Contrary to rumors, trees showing early-fall colors don’t always forecast a harsh, early winter. Usually when trees turn autumn color out of season, it’s because they’re suffering stress. Detective work is needed to pinpoint the cause of the stress and find possible remedies.
Autumn Blaze is a hybrid whose parents are red maple and the native silver maple. While iron chlorosis affects silver maple by turning leaves yellow with green veins, the deficiency in Autumn Blaze causes stress that has been known to bring on fall coloration.
Iron is sometimes adequate in soil, but trees can’t always utilize it. An application of a plant-available form of iron from the garden center might be advisable.
Other fall color-inducing stresses include too much or too little water and soil that is heavy or compacted.
Maples are adversely affected by improper planting depth. The widened “flare” between trunk and roots must be visible above soil line. If the tree goes straight into the ground like a telephone pole, it’s too deep and will suffer.
Check twigs for next year’s healthy plump buds, which are now being formed in the leaf “axils,” and scratch twigs to detect the healthy green layer underneath the outer brown/gray bark. This will help monitor the tree’s overall health.
Q: Our son and daughter-in-law will be moving into their first home in a new development in West Fargo. The yard is pretty much a blank slate.
Is planting trees in the fall a good time, or would it be better to wait until spring? Given the various tree diseases, what is your recommendation for species?
– Galen Schroeder, Fargo
A: Fall planting works very well. The tops won’t produce any additional growth, but the roots will continue to grow until soil temperature drops below about 40 degrees. This root growth gives fall-planted trees and shrubs a head start versus waiting until next spring.
Regarding types, North Dakota State University’s woody plants breeding program has produced great varieties that thrive. Local garden centers usually denote these on their descriptions.
Some favorites are Northern Acclaim Honeylocust, Prairie Expedition Elm, Prairie Reflections Laurel Willow (it’s non-weeping), Prairie Stature Oak, Northern Tribute River Birch, Dakota Pinnacle Birch, Prairie Dream Birch, and Prairie Torch Buckeye. It would be fun to have an all-NDSU yard!
Q: I am attaching photos of an invasive weed that plagues me. I see my neighbors growing it in their flower beds, but for me, it is a pest. Could you tell me what this is and how to control it?
– James M. Kaplan, Moorhead
A: The light purple bell-shaped flowers on rambling green stems are bellflowers of the genus Campanula. This group gives credence to the definition of a weed being “any plant out of place.” Some members of the Campanula group are nice perennial flowers like Joan Elliot clustered bellflower.
Other species of Campanula are iffier, even if they are in a flower garden. Some Campanulas spread profusely, weed-like, and become invasive, as you’ve experienced.
Creeping bellfower is nearly impossible to control by digging. Kill-all herbicides like Roundup can be effective, but it requires repeated applications on regrowth. Herbicides with 2,4-D labeled for hard-to-kill weeds also need multiple tries.
Death will come easier when the weeds are actively growing and lush in early spring. Fall is also a good time when weeds carry the poison downward into their roots as they store material for the upcoming winter. Mid-summer’s heat is less effective.
In some situations, weeds can be smothered by covering the area with black plastic, cardboard or even newspaper until the weeds run out of energy. Again, repeat may be necessary.
If you have a gardening or lawn care question, email Don Kinzler at ForumGrowingTogether@hotmail.com. Questions with broad appeal may be published, so please include your name, city and state for appropriate advice.