You are not alone in wondering! I have had countless questions on this subject. I have not heard of any increase in toxicities this year, but it is a popular question nonetheless! It seems that answering this question with the statement, “Don’t plant the following trees….” is not acceptable. I will do my best to give you some guidance as to what trees are both good and safe to grow in Maryland for shade in horse pastures and barnyards. Before I delve into that subject, however, I would still like to list the trees that are toxic to horses and give you some tips on whether or not you should leave existing trees in your pastures or remove them!
Red Maple – Cut this tree down with the help of a tree doctor if it’s in or near your pasture. Other varieties of maple trees are NOT toxic unless they have hybridized with red maple.
Oak – You don’t need to cut these trees down – provide plenty of palatable hay or grass and, most likely, your horses won’t eat the oak leaves. Fence the tree out so that the horses can’t eat the bark and have less access to acorns and leaves.
Black Walnut – The trees themselves, including the leaves, shouldn’t pose problems to your horses unless they are eating the entire tree. It is recommended not to cut down this tree if it’s in your horse pasture because that will actually increase the likelihood of toxicity as horses will then be walking through walnut sawdust. If you are still concerned, be sure to fence off the area once you’ve cut the trees in order to cut down on horse traffic through the sawdust.
Buckeye/Horse Chestnut – Fence these trees away from horses and provide plenty of hay so that your horses won’t be tempted to eat the leaves as they are one of the first to leaf out in the spring.
The following trees are good choices for shade trees in horse pastures; they are listed in order of growth rate (slow means the plant grows 12″ or less; medium means 13-24″; and fast means 25″ or more growth per year, respectively) so that you can decide how quickly you want the trees usable for shade. All of these trees are native to Maryland, so you can be sure that they will survive the hot summers and cool winters.
Hickory, Shagbark – mature height of 60-80 feet. Best along woodedges, bark peels off making the tree “dirty.” Shagbark is one of the fastest growing hickories, but it is slower than most other hardwoods such as oak. Slow growth.
Beech, American – Mature height of 50-70 feet. This tree is huge and does best with lots of space (width is almost the same as height!). Prefers sun. Slow-medium growth.
Hemlock, Eastern/Canadian – Mature height of 40-70 feet. Evergreen hedge when planted 2′ apart, used for windbreaks. Slow-medium growth.
Cedar, Eastern Red – Mature height of 40-50 feet. Good windbreak when planted in rows. Medium growth.
Birch, Yellow or River – Mature height of 40-75 feet, depending on variety. Medium-fast growth.
Hackberry, Common – Mature height of 40-60 feet. Tolerates many growing condions. Medium-fast growth.
Ash, Green or White – Mature height of 50-80 feet, depending on variety. Green Ash has a fast growth rate, White is medium.
Honeylocust, Common – Mature height of 30-70 feet. Adaptable tree that tolerates pollution, salty soil and drought. Fast growth.
Poplar, Tulip – Mature height of 70-90 feet. Prefers full sun and lots of space. Fast growth.
Erin Petersen, MS, PAS, Extension Horse Specialist
|This column is sponsored by the University of Maryland. the views expressed herein are those of the author and are not necessarily those of The Equiery’s publisher or staff. If you have a question for our Maryland Experts, you can e-mail it to either Dr. Amy Burk at firstname.lastname@example.org or Erin Petersen at email@example.com. If they can not answer your question directly, they will find the expert who can!|