AUGUST
2010

 

 

 

By
B. Rosie Lerner
 
Purdue
Extension
Consumer Horticulturist

 

 

 

 

 

08-05-10

Question and Answer


Q. We have over 350 pine trees around us. We are losing 1 or 2 every year. They turn reddish brown and die. They have all their needles; they just die. Is there anything I can do to stop this? We spray for bugs every year, mostly for bagworms.

A. There are many different species of pine, each susceptible to a number of different diseases, insect pests, and environmental stresses that can lead to decline and eventual tree death. White pine (Pinus strobus) in particular is quite prone to relatively sudden death. This syndrome is so common that it is actually been given the name "White Pine Decline" by plant pathologists.

The initial signs that the tree is in trouble can be a bit subtle; typically the tree owner will report that the tree just suddenly died, almost overnight. But if you look closely, the initial symptoms of decline include paler green, perhaps even yellowish, needles that are a bit shorter than in previous years' growth. The more recent years of twig growth are likely shorter than in the past. As summer heat and drought stress come on, the needles turn brown and the tree dies.

White Pine Decline is thought to be the result of a combination of factors, but the primary culprit is that the trees just are not well adapted to our soils and climate, despite the fact that they can put on relatively healthy, fast growth for their 10 ten years or so. They prefer light, well-drained soil and moderate temperatures. White pine does not tolerate wet feet, drought, high pH or extreme heat, all of which are common in Indiana.

In many cases, the pines are planted too close together when they are young trees so they may end up competing with one another, in addition to all the other stresses. If there is enough space to warrant replacing the trees, it is best to choose a better-adapted species rather than repeat with white pine.

Q. I have four Indiana Tulip trees. I got them expecting flowers. Now that they are quite large, I was told they never flower; they are just named that for the shape of the leaves. To my surprise, one tree had flowers shaped like tulips. They were green and yellow - and beautiful. Enclosed is a photo of one of the flowers. Can you tell me a little about this tree?
 
A. Also known as tulip poplar, tulipwood, yellow poplar and canoewood, the tuliptree is known botanically as Liriodendron tulipifera. Contrary to your being told that tuliptree never flowers, this tree was actually proclaimed the state flower of Indiana in 1923! It was then re-proclaimed the state tree of Indiana in 1931 and remains so today.

tulip tree bloom

Tuliptree's rather-interesting yellow blossoms do remind you of tulips. However, they often go unnoticed until they drop from the tree. This is due to being held upright and high on the limbs of tall, mature trees. As some of the common names suggest, the lumber was used for canoes, log cabins and furniture.

Native to most of the eastern half of the United States, the tuliptree prefers rich, moist, well-drained, loamy soil. The tuliptree can reach as tall as 190 feet where it is allowed to thrive, but it is more likely to reach 70 feet in height as a mature landscape specimen.

Additional information about the tuliptree can be found at
http://www.hort.purdue.edu/ext/state_tree.html and http://www.netstate.com/states/symb/trees/in_tulip_tree.htm.

Q. I have a trumpet vine (orange) planted 5 years ago in full sun, good soil. It has never bloomed. Why?

A. Although trumpet vine (trumpet creeper) is quite a vigorous vine, it can be a bit fussy when it comes to flowering. I get as many questions on how to kill this rampant vine as I do about why it won't bloom. The plant thrives in infertile soil; it seems the best flowering specimens are those that are neglected and never fertilized or watered. Fertilizer applied to the planting bed or even to surrounding lawns could cause the vine to expend its resources producing massive foliage at the expense of flowers.

The plant flowers on new season's growth so late spring or early summer pruning would remove the flower buds (winter or early spring pruning before new growth would be fine). Another possibility is that your plant was raised from seed and is still in a juvenile stage of development. It is not unusual for seedling plants to take 10 years or longer to become mature enough to flower.

 

 

Writer: B. Rosie Lerner
Editor: Olivia Maddox,