Why is my fir tree shaped differently and how should it be taken care of?
Question:
I’ve a fir tree which is around 20 years old. Some time ago it appeared to ‘morph’ to what it is now – like 2 different trees growing as one. The top part of the tree has multiple small pine cones growing on it. I am interested if you can shed any further light on the tree. Also, what could happen if I were to have the upper half of the tree cut down? It has grown quite tall over the past few/several years and now quite sure what to do with it at this stage of its life.
Answer:
What you’re seeing is something called genetic reversion. In horticulture, many ornamental features in plants, like variegated foliage or compact dwarf forms, were originally taken from a mutation or a witch’s broom on a normal individual of the species. The mutated portion (which continues the mutation in all subsequent cells grown from it) is then grown normally and propagated vegetatively by cuttings to sell as an ornamental “cultivar” (meaning “cultivated variety”). But the plant still carries the original DNA and will occasionally “revert” to its core instructions and begin producing new tissue like the original plant. In this particular case, your dwarf, conical white spruce (Picea alba) reverted at the point of that transition line, and has then continued growing like a regular white spruce does since then.
Unfortunately, the reversion is permanent so that top portion will continue to grow out in its tree form if left alone. Cutting out that section is the only way to reclaim the original ornamental shape, and you may need to monitor the cut stem for a couple of seasons to make sure it doesn’t continue to put out reverted growth. The bottom portion of the tree still looks reasonably healthy to me, though there is some needlecast at the bottom that could be pest- or pathogen-related, or could be symptomatic of the drought we’ve had. If the dead-looking areas progress, you might need to send a sample to the UMaine Plant Disease Diagnostic Lab for testing, and possibly follow up with a ME-licensed pesticide applicator for treatment, depending on what they find. But I don’t think cutting off the top part will hurt the rest of the tree.
Happy gardening.