Growing Together: Why did lawns look so crummy this spring?

Don Kinzler
Forum News Service

What’s your lawn philosophy? Do you meticulously groom and coddle each grass blade to perfection? Or maybe you only mow the lawn when searching where you left the wheelbarrow.

Many of us are somewhere between the two. No matter our lawn care viewpoint, many lawns around the region looked crummy this spring, and I received more emails and phone calls about the topic than any other gardening question in recent months.

Many lawns were badly matted, thin, anemic-looking, riddled with dead patches, dotted with small dirt blotches and bumpy enough to turn an ankle while walking.

What happened? A series of separate lawn plagues all descended since last fall, causing multiple disorders. Let’s examine them each, with recommended solutions.

Matted, moldy grass

When snow disappeared this spring, many lawns were matted down, often with gray or pink moldy patches. Snow came early, stayed late, and grass suffered under the weight and longevity of cover.

Fluffing up the grass by raking is the best medicine, which has been accomplished on most lawns by now. The mold usually disappears quickly by raking, but can kill grass patches if left in its matted condition.

Bumpy lawn, small dirt mounds

The next issue to appear on many lawns was a multitude of small, half dollar-sized mounds of soil sprinkled through the lawn, making the lawn not only unsightly, but the bumpiness is like walking across a field of golf balls. The cause has been nightcrawlers and other earthworms working very close to the soil surface due to last fall’s heavy rains making soil supersaturated.

Alan Zuk, a turf management professor at North Dakota State University, says the bumps are called “worm castings” and can be mitigated by light power raking. He indicates earthworms are protected species, so we’re not allowed to use chemicals to control them. There are no pesticides labeled for nightcrawler and other earthworm control.

As lawns dry, worms tend to move deeper into the soil. When watering lawns, water deeply and less often to encourage worms to move deeper.

Yellow, anemic-looking turf

Many lawns began spring looking more like a patchwork of yellow mixed with light green than a uniform rich emerald color, with several probable causes.

Heavy rains last fall and generous snow melt might have leached nitrogen away from grass roots, leaving turf nutritionally deficient. Grass plants might also be low in iron, causing yellow, chlorotic conditions common when soil is cold and wet, as it’s been this spring.

To remedy pale turf, apply lawn fertilizer following label rates and instructions. Fertilizers containing iron can restore green color if iron deficiency is suspected. Lawns are best able to utilize fertilizer most efficiently after the grass is green, actively growing and soils have warmed as we get closer to Memorial Day. As soil warms naturally, many lawns improve as grass roots become more active and can utilize existing soil elements.

A soil test gives a good analysis of the current soil quality. Information for submitting samples to the NDSU Soil Testing Lab can be found at; University of Minnesota soil testing information can be found at

Lawn care recommendations

Turf becomes most healthy when we give grass its natural preferences over extended years. Roots grow deeper, weeds are reduced and the lawn becomes more self-sustaining with the following recommendations.

Autumn is vital to grass health, as roots grow deep and nutrition is stored for winter survival and early spring growth. Fertilizing around Labor Day is the single most effective time for long-term lawn health. Apply again around Memorial Day.

When sprinkling lawns, water deeply and less frequently, providing 1 inch per week in one application, or two if soil is sandy. Raise the mowing height to 3 inches; low mowing causes a weaker turf. Let grass clippings filter back into the lawn; they release nutrition as they decay, plus conserve moisture and block weeds.

Fielding questions

Q: I have a September Ruby apple tree that was mauled by rabbits this winter. We had the trunk wrapped, but the snow got higher than the wrap and they chewed off bark all around the trunk. I thought it was dead after reading online that’s what usually happens, but it is budding and leafing out! This tree is a memorial for our stillborn daughter and I will do anything I can to save it. Can you help? — Sara, Fargo.

A: Let’s do everything we can to save this tree, but for now, the best thing to do with your September Ruby apple is wait and see.

Once bark is damaged by rabbits, there are no paints or sealers that should be applied. Trunk recovery is best hastened by exposure to air. Trees can compartmentalize damage, and if enough of the conducting tissue is undamaged, some trees show remarkable ability to survive.

But such damage can also cause death to the tree portions above the point of injury. Damaged trees sometimes have enough internal sap and energy reserves to leaf out in spring, but when leaves fully expand, and summer arrives, the damaged tissue might not be able to conduct water and nutrients effectively within the tree. Wilting and death of leaves and branches frequently happens at that point.

If that happens, there’s a backup plan. Rabbit injury to a trunk usually doesn’t kill the tree’s roots, and your tree wrap protected a fair amount of the trunk. If the tree’s portion above the injury dies, the lower trunk will most likely sprout and continue growth. If so, carefully cut off the tree trunk above that point and allow the sprouts to grow, which can be trained into a new trunk. Please keep us posted.

Q: What do you recommend for preparing soil in a yard that has always been grass if you’d like to convert an area to a vegetable garden or flower bed? — Deb Haugen, Fargo.

A: After the turf layer is either killed or stripped away, adding organic material is a great way to prepare soil for vegetable or flower gardens, especially if the soil is heavy clay or light sand.

Add a 3-inch layer of peat moss, compost or bagged manure, then incorporate into the soil by digging or rototilling. Organic materials improve the tilth and workability of soil, allow better moisture and air exchange, and improve the nutrient-holding capacity. Organic material is somewhat of a cure-all for both too-heavy and too-light soils.

Q: My shrubs in the yard are not showing much evidence of growth. Is it a late spring, or is this evidence of winterkill? Should I trim them down? — Mike Richtarich, Britt, Minn.

A: As springs go, this would probably be considered somewhat late for tree, shrub and perennial flower startup. Besides air temperature, these plants also respond to soil temperature, which has been chilly for roots. As both air and soil temperatures warm more consistently, growth is triggered.

Winterkill is always a possibility, especially on any plant material that’s borderline in winter hardiness. Because there’s no way to speed a plant’s spring startup, it’s not always clear whether plants are slow or winterkilled. It’s best to simply wait, and see what happens.

Most live plants will begin growth at least by late May or early June. Many shrubs, even if injured by cold or critters, have amazing ability to regrow from the base. If all regrowth begins at the lower portions, prune away the dead branches above.

Even while dormant, live branches on shrubs and trees can be determined by the presence of the green cambium layer, visible when the outer gray-brown bark is gently scraped away with a thumbnail or knife.

Many lawns in the area have been thin and patchy this spring.
A reader asks if it’s possible to save this apple tree that was damaged by rabbits over the winter.