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A Mutation for the Season

Add witches broom to your ­Halloween hunt

A Bay Weekly reader asked if I had seen an odd-looking pine tree growing on the west side of Rt. 4 about a quarter-mile south of the Patuxent River Bridge.
    It’s a witches broom, and I have been admiring it for at least 10 years. The tree is some 20 feet tall and grows on the edge of the woods about 100 feet from the side of the road.
    Witches brooms are abnormal dense growth on a branch or stem of a tree or shrub. On high-bush blueberries, they are caused by bacteria and are detrimental to the plant. The infected plants should be dug up and burnt to prevent the spread of this disease.

How to Prepare Your Leaves for Composting

Broken and shredded leaves compost faster than whole leaves. Grind up fallen leaves with the lawnmower, or let the kids jump and romp through piles — before you place them in the compost bin. If you have a shredder, use the fine screen to pulverize the leaves and they will compost even faster.

    Witches broom on confiners such as pine, spruce, fir or hemlock are typically caused by a genetic mutation.
    When I was an undergraduate at the University of New Hampshire, one of the faculty was interested in collecting and trying to propagate witches-brooms by rooting cuttings. The man was single, and did most of his collecting on weekends. We would travel the country roads looking for them, and I would climb the trees to gather samples.
    When a small article on his witches broom studies appeared in the state newspaper, The Union Leader, he was flooded with leads throughout the state. We spent many weekends collecting samples. He soon discovered a plant scientist in Connecticut with a similar interest, and the two exchange samples and results.
    Of the thousands of cuttings we harvested, we were never able to obtain rooting. However, one day I found small cones on a hemlock witches broom we had collected near my home in New Hampshire. We were able to germinate seeds from the cones. Long after I had come to Maryland to complete my studies, my old professor informed me that those seedlings had developed into small compact shrubs with strong dwarf characteristics. The scientist in Connecticut made a similar discovery from cones produced by witches broom on pine and fir.
    Neither of the plant scientists was ever able to clone the witches broom by rooting cuttings.
    The next time you are traveling south on Rt. 4, look to the right after you pass the little shopping center south of the Patuxent River Bridge. Look smart and you’ll see the witches broom growing on a Virginia pine.

Ask Dr. Gouin your questions at [email protected]. All questions will appear in Bay Weekly. Please include your name and address.