Leaves tell outdoor stories

Jerry Davis For Agri-View

Plant leaves – most plants have them – can be an outdoor enthusiast’s health check of the environment, weather forecast, seasons calendar, rain gauge, insect-population survey and more. Some plant groups have specific names for their leaves. Needles belong to pines, spruces and tamaracks. Fronds are found on ferns such as polypodium ferns. Flower parts – petals and sepals – are modified leaves. They act leafy – abscising, wilting, color-changing and blowing in the wind.

Leaves can identify a plant. They indicate if it’s a sugar maple or a silver maple. If the tree is leafless, scan the ground for old leaves. American chestnut, mulberry, hackberry and poison ivy are easy to read.

Leaves are a plant’s respiratory system, taking in carbon dioxide. They release oxygen, sometimes liquid water and other times water vapor when leaves are open to dry air. Leaves are the main photosynthesis organ for trees; the greener they are usually means the more energy is being stored for wood and fruit growth. More lumber is being laid down radially and acorns are going to have energy to fill out. White oak in particular is often short on iron nutrients; leaves suffer from chlorosis and remain yellowish-green.

The dark-green leaves of soybeans advertise optimal photosynthesis. That would be expected because those legumes have an association with bacteria to fix nitrogen. Corn needs more fertilizer applications.

Most trees have currently finished growing longitudinally, but some trees have put on a second flush of growth. It’s been a good growing season for leaves; those new leaves of summer are a different shade of green for a few weeks.

If entire leaves and young stems are missing on tomato plants, yes, the tobacco hookworm caterpillar is living on tomato tissues. If larger-still portions are missing on tomatoes, a whitetail has jumped the fence. Holes in bean leaves means Japanese beetles have returned.

Black walnuts are beginning to show yellow leaflets. It’s a fungus, anthracnose, which attacks leaves on a branch. They turn yellow just as though autumn was here; it’s premature fall caused by a disease.

Diseases infect all plant organs, including leaves. Some infections make host-plant identity unmistakable and rather interesting to look at. Elderberry leaves may have banana-like growth. Goldenrod stems have enlarged stems. Many diseases are species-specific.

Any stress may make tree leaves look like fall, but it probably isn’t. When all the leaves on an elm turn brown and begin to fall off, morel hunters rejoice for next April and May. Mark the dying elm tree as being a place to look.

Real autumn-like reactions occur now in woodbine. One – or more – of the five leaflets on the compound leaves turns beautiful red and drops as a leaflet, not an entire leaf. Real fall does a number on most leaves and upsets their pigment balance, wiping out the green chlorophyll. Then red, brown and yellow pigments rule inside woodland leaves.

Stickseed is a weed known for frustrating any autumn outdoorsperson when clingy chains of tiny fruits attach to autumn attire. The basal leaves on the single stem die and turn a deadly black like no other plant in woodland edges and openings. Pull the plant now before it blooms and fruits.

Blackberries are beginning to be a source of breakfast fruit. Leaves on late-season crabgrass are lime-green but then they always are on the warm-weather grass. Prairies are yellow with sunflowers and coneflowers but waiting for great blue lobelia and bottle gentian.

Corn, alfalfa and soybean fields look great. Husks are covering fruits on corn, hazelnut and American chestnut. Wild ginseng is heavy with green fruits but shows no signs of yellowing leaves and crimson berries. Mushrooms continue to pop up and just as quickly deliquesce into a heap of black mush. Joe-Pye weed is turning tall and purple.

This is an original article written for Agri-View, a Lee Enterprises agricultural publication based in Madison, Wisconsin. Visit AgriView.com for more information.