Do they cause root damage to close buildings?
Alder Trees have a large and expansive root system.
You should consider this tree an invasive root system tree.
Please can you help? I woke up this morning and my two beautiful Alder trees seem to be leaching a type of what looks like oil (or maybe sap). The tree trunks have gone black from the roots half way up the trunks. When I touch the trunks it almost looks and feels like it has been sprayed with oil? Its spring in New Zealand now and I noticed the leaves on the trees are small. I have heard of trees which run sap when under stress but I thought sap was sticky this is like an oil and has a sweet smell not unlike Pine Oil. I am upset as we have fought our neighbours in court to keep these trees I am just hoping they have not been over and sprayed some type of oil on the trunks. Surely not. If you can help at least by identifying is sap a type of oil it would help me. Many Thanks Rosemary Riddle.
The sap of some trees is darker and can appear oily. Common reasons for trees to leak sap are physical injury, bacterial or fungal diseases, environmental stress, or insect damage. If you don't see any physical injuries on the trees, check for symptoms of bacterial disease:
One form of bacterial disease affecting alders in New Zealand is below:
If the problem persists, you may want to consult an arborist or university extension service professional to help with diagnosis and treatment.
Alnus glutinosa (black alder) has recently been added to a list of 44 newly-banned invasives in Indiana. While the ban will not be legally in place until our governor signs it, I hope that you will change the information on your website which recommends planting black alder in the US.
Thank you for your observation. I will forward your comment to the editor for review.
Though pruning can promote branching, it can also weaken the structure over time. Have care when pruning, and only leave branches that are angled upwards, and not horizontal.
Here is an article for more information on the tree:
Hi guys I would really appreciate some expert advice. I am planting a bare root Italian alder hedge. 7 whips per metre in two staggered rows ie a row of 4 and then a row of 3. The hedge is going to be planted next to a wooden sleeper retaining wall.i would like to keep the hedge as narrow as possible. Q1. How far from the sleeper wall can I plant row 1. Q2. In row 1 the whips are 33cm apart. Row 2 is staggered with row 1. But how close can I plant the second row to row 1 please? Thanks in advance!!
My research showed 40 to 50 cm between rows. Also, I read that Italian alder roots are invasive and should be planted 30 meters from structures.
Here's more info that may be helpful:
Two alder trees started growing in a pot in my backyard this spring and I’m beginning to like them and thinking I could plant them in the ground in the same spot. Is this going to be bad for the foundation directly next to it? My yard is really small, so there isn’t much room to move it away, but I could go about a foot away from the concrete.
I'm afraid that it would be a very bad idea. You could try growing it in container, though:
We have a large Mature Alder tree that was growing near some pylon. The local Electricity supply company took the tree down to 1 metre instead of 6 metres. We have lost all privacy in that part of the garden and wish to have a bunch of Alder branches grafted on to reduce the time we have to wait to get our privacy back. It will be made good at their expense. Can it be done, and if so how big can the branches be that get spliced in?
This can be done, but it will need to be done with very small buds grafted on at the correct time. Here are some articles that will help you to get started:
Generally, you can use small branches, but the larger the branch you use the more likely that it will fail. This is why buds are preferred.
That does not really help, It will not be me doing the work, I expect the Electricity Supply company to bear the cost and supply an expert at doing this. I want to know how hard to push back to them. Another possibility is to push them to provide a replacement tree of about 8 metres tall!
It I insist upon splicing, how many 1-2 inch splices would it take to get 3 successful splices?