Previously healthy tree of 20 metres suddenly leaves turned brown and over a six week period still brown but not dropping much.
Yes, wait and see how it does this spring and summer. It may be frost damage, from the characteristic partial browning on one side. If a hard freeze is sustained for a few days the Eucs can be killed; if only for a night or two, they brown like yours and then recover the next growing season.
Consider creating a drainage system for the lower property; dig a channel, install drain tiles or whatever is appropriate.
https://www.gardeningknowhow.com/ornamental/trees/eucalyptus/eucalyptus-cold-damage.htm
https://www.gardeningknowhow.com/ornamental/trees/eucalyptus/eucalyptus-tree-root-damage.htm
I brought in my eucalyptus plant (about 4 ft tall) at the beginning of Oct and it was doing ok. Earlier last week I noticed the tips are becoming brittle and dried. I watered the whole plant very well because I thought it might be dried. but now all the leaves super crispy and it's all falling off with the slightest touch...
It sounds like it suffered an infection from overwatering. This could have been mistaken for needing water, which when given will worsen the issue.
You can attempt correction with a fungicide. Usually, in container, any infections left to progress are fatal.
This article will help you with fungicide use: https://www.gardeningknowhow.com/garden-how-to/info/using-fungicides-in-garden.htm
This article will help you with the care of the tree: https://www.gardeningknowhow.com/ornamental/trees/eucalyptus/eucalyptus-houseplants.htm
Hello. Our tree over the last six months, as been dropping dead limbs so we have started cutting back dead limbs before they drop. We have also noticed what appears to be a fungi on the outside of trees that were are treating with eucalyptus which more recently appears to be eliminating the fungi. is there any more we can do to help the old tree Regards David
From what you describe, it may be Armillaria root rot, a common fungal disease. Symptoms include decline in tree health, susceptibility to pests and die-back, canker on the lower trunk and mushrooms at the base of the tree.
This is bad news for you and your tree. Unfortunately there is no definitive cure. And at an advanced stage of infection and decay of the roots and root crown at the base of the tree, considerable loss of conductive tissue has occurred and will limit uptake of water and nutrients, and therefore cause die-back/limb loss and susceptibility to pests and foliar diseases.
An all-out effort to save the tree could get expensive, and is not a sure thing. I suggest soil testing and prescription of mineral and biological amendments based on nutrient deficiencies found. This would not insure a cure, but would help to give the tree the best possible conditions to resist advance of the fungus.
https://www.gardeningknowhow.com/plant-problems/disease/armillaria-root-rot-control.htm
I bought a small one with a mint plant and a chamomile plant. the other two have scents, though very mild, but my eucalyptus plant has absolutely no scent. Is that normal? Its very small, only two sprigs
Yes, many plants will not have a smell until they are mature enough. This can vary from species to species, and even from plant to plant!
These articles will help you to care for your plants properly: https://www.gardeningknowhow.com/edible/herbs/chamomile/growing-chamomile.htm
https://www.gardeningknowhow.com/ornamental/trees/eucalyptus/tips-growing-eucalyptus.htm
https://www.gardeningknowhow.com/edible/herbs/mint/mint-plant-varieties.htm
Are the roots of these trees a problem close to houses and is there a recommended distance they should be planted away from street houses and drains. Do their limbs drop?
Here's an article that may help:
https://www.gardeningknowhow.com/ornamental/trees/eucalyptus/eucalyptus-tree-root-damage.htm
https://www.gardeningknowhow.com/ornamental/trees/eucalyptus/eucalyptus-pruning.htm
The plant gets lots of ligt, i water it so the soil doesnt dry out. The new leaves are very fragile, thin, but not papery. They are curling and twisting and are very silvery. And now even the big, older and more robust leaves are starting to get wavy. The plant grows quickly and grows new little branches nd leaves. It si just not the healthy, flat and round leaves you see when you look up Eucalyptus Gunnii on the internet.
It is probably well overwatered if it does not get a chance to dry out between waterings. The soil should be allowed to dry, completely, down to about 2 or 3 inches between waterings. This will help prevent rot, or root suffocation.
Here is an article to help you with the care of the tree in container: https://www.gardeningknowhow.com/ornamental/trees/eucalyptus/eucalyptus-houseplants.htm
my eucalyptus tree [established] has gone brown on several branches and can be snapped off. Also a new hydrangea shrub has gotten the same brown leaf and seems to have died.
These articles discuss diseases of the plants that you are referencing.
https://www.gardeningknowhow.com/ornamental/trees/eucalyptus/eucalyptus-tree-problems.htm
https://www.gardeningknowhow.com/ornamental/shrubs/hydrangea/common-hydrangea-diseases.htm