Why Is My Juniper Turning Brown?
Discovering why your juniper bonsai is turning brown is essential for its well-being. Browning leaves and a withered trunk can be attributed to two main causes: underwatering or excessive water. Underwatering or insufficient water supply may lead to leaf browning and a dehydrated trunk. Conversely, overwatering can result in water stagnation, causing root rot and brown leaves. Understanding these distinctions is vital in addressing the health of your juniper bonsai.
Lets take a deeper look into the common issues that cause browning.
Interior Foliage Browning
Each spring you will get a new flush of new needles all over your juniper, this can quickly make the tree become very dense and thick. We do always say to allow this first flush to happen and harden off before you start pruning your tree to allow the strength to balance back out as the tree used energy to put that growth out so you want to allow that growth to give energy back to the tree. In this process however what happens Is the growth that is closer to the trunk which we call the interior foliage is getting shaded out from the sun which can cause it to become weak and the tree will begin to drop that foliage. This will cause the interior foliage to become brown, brittle and fall off. In this situation this is completely normal and there is no need for alarm. As you move to late spring / early summer though you will want to give the tree a good prune and allow air and light to get into those interior areas so the tree can grow new buds in there which you can use to cut back to in future to keep the shape of your tree as it starts to out grow its silhouette, When this work is not done this is when you will see junipers with long leggy branching.
Branch Tips Browning
When a juniper begins to brown off from the tips of the branches this is when you have a problem, The first thing to look at is if all the branches on the tree have browning tips or if it is isolated to an area on the tree such as the very top or even a single branch. Sometimes this can be caused by damage during wiring or if the tree has blown over and broken a branch. If every branch on the tree has browning tips then it is likely your whole tree has died and that browning will continue to move back towards the trunk until eventually the whole tree is dry, brown and brittle, and normally this death has occurred about 8 weeks prior as junipers take a long time to show signs of death. I have had branches I’ve cut off a juniper stay green for 6 weeks!
The tips browning can also be caused by poor pruning technique which we will talk about further later, but if this is the case you will likely know that you have caused the browning by cutting through the needles.
What causes brown foliage on Junipers?
There can be a few things but here are a few common things to look at first
Watering : if the tree was allowed to dry out excessively this can cause the root tips to dry out and die, with all bonsai you need to keep some amount of moisture present in the soil to ensure the root tips stay hydrated. On the other hand you can also overwater your tree but this usually takes longer ( a period of 2 months or so of excessive watering ). But in my experience over watering is usually more of a problem with a poor soil mix that doesn’t drain well and is too dense which tends to hold onto water in the bottom parts of the pot causing root rot.
Wiring Damage : this is something that might not be so obvious, a juniper branch can be damaged during wiring with no external signs of that damage. When you wire up a branch you see no breaks or cracks but weeks later you begin to see the branch dying, what gives? The inner tissues of a tree can tear causing the branch to no longer be able to take up moisture which leads to the branch and foliage drying out and dying. Larger bends are better left to late summer / early autumn to help avoid internal damage during wiring.
Excessive root pruning / Wrong Timing : When working on junipers a good rule of thumb is to not remove more then 30% of the roots in a single working, The healthier your tree is and the better your timing the more you can push that boundary. When starting out though start off in the safe zone of 30% and time it for early winter when the weather begins to warm up again. Make sure your clear of any sudden frosts or cold snaps. You will want to do any root work before the weather becomes too hot as the tree will transpire faster then it can take up water due to the temporarily compromised root system and likely die or lose branches.
Poor Pruning Technique : When pruning a juniper it is important that you cut through the main stems to prune them back and not through the needles, cutting through the needles will cause the cut needles to turn brown and die back. This will cause the tree to look like it is dying if you have pruned the whole entire tree but if you are aware that you pruned it by hedge pruning and cutting through the needles then you have a good idea of what cause it to turn brown.
Now there are other things that can affect your juniper such as pests like spider mites and disease, over pruning and poor maintenance but what is listed above are usually the main causes of browning leaves on juniper bonsai.
Check out our Ebook Care Guide For Junipers
I hope this article has helped you with your search for answers to why junipers turn brown.