Plant Healthcare

Caring for Mature Trees

Caring for Mature Trees Caring for Mature Trees. Mature trees are valuable assets to any property—providing shade, beauty, and environmental benefits. Unlike young trees, they require a more thoughtful approach to care, focusing on preservation rather than rapid growth. Start with regular inspections. Look for dead or hanging branches, cracks in the trunk, fungal growth, or thinning canopy. These can be early signs of stress, disease, or structural concerns. Catching issues early allows for safer and more effective treatment. Pruning is one of the most important maintenance practices. Mature trees […]

Signs of a Stressed Tree

Signs of a Stressed Tree Signs of a Stressed Tree include premature leaf drop, yellowing or browning leaves, a sparse canopy, and early fall colors. Other indicators are wilting, leaf scorch, bark problems like splitting or flaking, reduced growth, and unusual amounts of seed or cone production. Wisconsin’s weather, from heat waves to droughts, can cause many of these issues, making trees vulnerable to pests and diseases. Leaf and canopy symptoms Premature leaf drop: Leaves fall off the tree sooner than they should. Wilting or browning leaves: Leaves […]

What’s Killing My Hackberry Tree?

What’s Killing My Hackberry Tree? What’s Killing My Hackberry Tree? Hackberry trees are tough and adaptable, but they are not immune to problems. If your hackberry is declining, the cause could be insects, disease, weather stress, or root damage. One common issue is hackberry nipple gall or witches’ broom, which can make the tree look unhealthy. These problems often look alarming, but they usually do not kill the tree on their own. More serious concerns include root injury, soil compaction, construction damage, and long periods of drought or excessive moisture. […]

Not Your Average Mistletoe

Not Your Average Mistletoe Not Your Average Mistletoe. Eastern dwarf mistletoe (Arceuthobium pusillum) is a small but highly destructive parasitic plant that primarily affects spruce trees across northern regions, including parts of Wisconsin. Despite its tiny size, this plant can have a major impact on tree health, often going unnoticed until significant damage has already occurred. Unlike traditional plants, Eastern dwarf mistletoe attaches itself directly to its host tree and draws water and nutrients from it. Over time, this weakens the tree, slowing growth and making it more vulnerable to […]

Mild Winters and Tree Health

Mild Winters and Tree Health Mild Winters and Tree Health. Milder winters across Wisconsin are becoming more common, and while they may feel like a relief compared to harsh cold snaps, they can have unexpected effects on your trees. Winter plays an important role in a tree’s natural cycle, helping regulate growth, control pests, and prepare trees for the next growing season. One of the biggest impacts of a mild winter is reduced dormancy. Trees rely on consistent cold temperatures to fully “rest.” When winters are warmer, trees may not […]

Cedar-Apple Rust

Cedar-Apple Rust Cedar-Apple Rust is a fungal disease caused by Gymnosporangium juniperi-virginianae that requires two hosts to complete its life cycle: juniper species (like eastern redcedar) and apple/crabapple trees. It appears as brown, kidney-shaped galls on cedars that develop bright orange, jelly-like horns in wet spring weather, releasing spores that infect apple trees, causing yellow spots on leaves and fruit. While it’s not very harmful to junipers, it can cause significant damage to apples, leading to premature defoliation and poor fruit quality. Life Cycle of the Fungus On […]

Bur Oak Blight (BOB)

Bur Oak Blight (BOB) Bur Oak Blight (BOB) is a fungal disease that causes leaves to develop wedge-shaped, brown lesions and remain on the tree into winter. Treatment involves fungicide trunk injections by a qualified Arborist, and leaf litter removal can reduce fungal spores.Preventative measures like maintaining tree health and proper watering also help, but BOB is best managed with professional diagnosis and treatment. What is Bur Oak Blight? Cause: A fungal disease that primarily affects bur oak trees in the Midwest. Symptoms: Purple-brown lesions along the […]

Hypoxylon Canker

Hypoxylon Canker Hypoxylon canker is a serious disease of aspen and other trees, often killing stressed or weakened trees.It’s characterized by the appearance of large, black or grey, spore-bearing mats (stromata) on the bark, usually in areas affected by drought or other severe stress. There is no direct treatment for the fungus once symptoms appear; however, managing tree health by watering and preventing stress can help, and pruning out infected branches can prevent further spread in less severe cases. What is it? Hypoxylon canker is caused by a fungus […]

Northern Tooth Fungus (Climacodon septentrionalis)

Northern Tooth Fungus (Climacodon septentrionalis) Northern Tooth Fungus (Climacodon septentrionalis) is a parasitic, shelf-like fungus that causes heartwood rot in hardwood trees, particularly maple trees.There is no known cure for the infection, but trees can be managed by maintaining their health, avoiding wounds to the trunk, and having a certified arborist perform a risk assessment to determine if the tree needs removal. What it is A parasite: The fungus enters trees through wounds and lives in the central heartwood. Visual identification: It forms large, overlapping clusters of […]

Recent Tree Health Threats

Recent Tree Health Threats Recent Tree Health ThreatsWhat’s New in Tree Health & Forest Threats- Wisconsin Department of Natural Resources (DNR)’s 2025 forest-health alerts In December 2025, the DNR advised property owners to watch for woodpecker “flecking” on ash trees — a tell-tale sign that Emerald Ash Borer (EAB) may be present. This invasive beetle remains “the most damaging threat to Wisconsin trees,” capable of killing ash trees over a few years if untreated. forestrynews.blogs.govdelivery.com+1 Also in late 2025: DNR foresters are continuing to monitor other invasive pests even if […]

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