The Madman and The Tree-Of-Heaven

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The madman was sure that we had Tree-of-Heaven sprouting all over. The two popping up in the Blueberry patch got his attention. So, when a reader sent us a picture of a problem tree in her yard, he was off the races and research began in earnest.

seedling with serrated leaves — *Since this is in the Blueberry patch, the madman was delighted to see the serrated leaves signifying it was not a Tree -of-Heaven.*

Tree-of-Heaven

Contrary to its name, Tree-of-Heaven (Ailanthus altissima) is one bad plant. Like most invasive plants we are currently dealing with, this plant was introduced on purpose. In the 1700s, horticulturalists brought it to Philadelphia as a specimen and shade tree.

Its ability to grow straight and fast earned it the nickname Tree-of-Heaven. In a good year, it can grow 5 feet, eventually reaching a height of 70’. As the main trunk grows upwards, the roots begin to expand and sucker. One tree can create an entire grove. You can understand the madman’s concern.

Grove of Tree-of-Heaven trees — *One Tree-of-Heaven can quickly turn into a grove. Image by Richard Gardner, Bugwood.org.*

Banned in Connecticut

Although the planting, sale or transport of the tree is banned in Connecticut, it is still available in the nursery trade. Why, you may ask? Sellers tout the fact that it is a rapid grower that thrives in various soils (the madman says it grows any place but the deep dark woods). Tree-of-Heaven has few pest problems and tolerates pollution, making it a good urban street tree.

Sellers claim that its tropical appearance adds an exotic ambiance to the landscape. One nursery even brags that since a tree produces 325,000 seeds per year, it guarantees the rapid spread of the plant and ensures the plant’s continuity.

Tree-of-Heaven plant — *Despite its tropical appearance, Tree-of-Heaven is nasty. Image by Richard Gardner, Bugwood.org.*

Stinky Tree

All of this ignores the fact that it stinks – all parts stink, but the male flowers are the worst. And its rapid growth crowds out our native plants. If that’s not bad enough, Tree-of-Heaven is allelopathic, emitting a chemical called Ailanthone that can inhibit or even kill neighboring plants.

But there is no denying that it is an exotic looking plant. The compound leaves can grow 11 to 36 inches in length and contain 10-41 leaflets, making it look like a palm tree. The pointed leaves are smooth, with a couple of roundish nodes near the petiole (where the leaflet joins the stem).

Bottom view of Tree-of-Heaven leaflet — *Tree-of-Heaven can be identified by distinctive leaf nodules near the base of the leaflet. Image by Annemarie Smith, ODNR Division of Forestry, Bugwood.org.*

Trees produce either male or female flowers that are small and yellowish in color, growing together in panicles that may be up to 20” long. As we said, the male flowers stink, a trait that attracts all sorts of pollinating insects. The female trees produce samaras, or helicopter seeds that are easily carried great distances by the wind.

Seeds of the Tree-of-Heaven — An adult Tree-of-Heaven produces lots of these distinctive samaras. *Image by Annemarie Smith, ODNR Division of Forestry, Bugwood.org.*

Look Alikes

Positive identification of this plant can be tricky because of the look-alikes out there. Our native Staghorn Sumac (Rhus typhina) bears the closest resemblance. Especially when the plants are young. But, while the leaves of Tree-of-Heaven are smooth, the leaves of Staghorn Sumac are serrated. The fruits too are quite different. Tree-of-Heaven forms clusters of samaras while Sumac has reddish cone-shaped clusters of fruits. Although some suggest the dwarf-winged sumac (Rhus copaline) as a look-alike, the madman feels that its leaves are too fat to be confused.

Staghorn Sumac showing fruit cluster — *A common look-alike is the Staghorn Sumac. Image by Ohio State Weed Lab, The Ohio State University, Bugwood.org.*

What does confuse him are seedlings of Black Walnut (Juglans nigra). Our four-legged gardeners plant these nuts all over in our soft garden soil. We have no idea where they get the black Walnuts, because we don’t have one growing near us. But, every spring, we get a few sprouts. Again, it has serrated, not smooth, leaflets. Because this plant is also allelopathic, the madman feels it should be pulled as fast as Tree-of-Heaven.

Small black walnut tree — *Black Walnut seedlings are often confused with Tree-of-Heaven. Image by Paul Wray, Iowa State University, Bugwood.org.*

Thorny Identification

Interestingly, none of these trees has thorns. However, in her query, our reader mentioned thorns. The madman’s research convinced him that the tree in question is some sort of locust as locusts have compound leaves and thorns. Since both the Honey Locust and Black Locust are quick to spread, he would get rid of them.

thorns along the base of a Black Locust tree — *Black Locust seedlings have compound leaves, but also have thorns. The madman doesn’t like these. Image by Jan Samanek, Phytosanitary Administration, Bugwood.org.*

Spotted Lantern Fly

But, now back to the Tree-of-Heaven. We mentioned earlier that pollinators like the flowers. Unfortunately, it’s a favorite of the Spotted Lantern Fly (Lycorma delicatula), a bug that is striking terror in the hearts of agricultural experts in the Northeast. It was first detected in September 2014 in Berks County, Pennsylvania. Since then, it has been spreading into neighboring states due to its ability to grab onto a bumper or anything else and hitchhike along. The madman feels this is how it found its way up I-95 into Fairfield County which has a high concentration of Tree-of-Heaven.

Not A Fussy Eater

Although its favorite host plant is the Tree-of-Heaven, it will attack 60 genera of the trees and plants of North America. In Connecticut, grapes, apples, stone fruits and 40% of our forest trees are considered susceptible. This explains the terror among the agricultural experts. The full scope of the potential damage is unknown, but it can be high.

Lifecycle

The Spotted Lantern Fly hatches and goes through four instars before becoming an adult. These adults appear in late July and start feeding preferably on Tree-of-Heaven and on grapes – so now is the time to actively look for them. The fore wings are light brown, and the hind wings are a bright red and black. The best time to look for them is at dusk as they migrate up and down the trunk of a plant. During the day, they tend to hide out at the base of a tree in cover.

adult Spotted Lantern Flies near the ground — *Spotted Lantern Flies clustered at the base of a tree. Image by Richard Gardner, Bugwood.org.*

Egg laying begins in September and hatching begins the following May. The Connecticut Agricultural Experiment Station (CAES) has prepared an excellent article on the invasive Spotted Lantern Fly. All stages of the insect feed by piercing and sucking. This can disrupt photosynthesis and weaken the plant. As they eat, they excrete a substance known as honeydew which can promote the growth of a black mold. Not only is the mold unsightly, but it also attracts stinging insects – and you know how much the madman likes stinging insects.

Nymphs climbing along a shoot — *Infestation of Spotted Lantern Fly nymphs on a Tree-of-Heaven. Image by Richard Gardner, Bugwood.org.*

Rat Them Out

If you see one, take a bunch of photos (pixels are cheap) and call CAES 203-974-8500 for further instructions. Do the environment a big favor and get rid of any Tree-of-Heaven plant you find (Check out this CAES quick guide). Also remember to clean your shoes if you hike in any natural area or trail – remember, PlayCleanGo and, don’t you dare transport any firewood out of your county.

Much to the madman’s relief, we aren’t dealing with Tree-of-Heaven in the blueberries. But, just the same, those Black Walnuts have to go. First, some lemonade.

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