Well, get off that knee and let's see if we can figure this out.* :)* Since this is the container gardening forum, I'm guessing your tree is in a pot.* Pretty good so far, eh?* I'm also thinking you have checked to see if it's rootbound, in full sun, the soil is staying wet or there is a saucer under the pot and water collects in it.* Those could all be causes for the problem.*
Not sure what you mean by "lighter lines round all the leaves".* Can you post a picture?
You used the word "ropey" and I've never heard of that word so I looked it up.* Do you mean droopy?* That can come from overwatering.* If it's been windy that can cause the leaves to be scorched too.* Take a look here.
When weeding, the best way to make sure you are removing a weed and not a valuable plant is to pull on it. If it comes out of the ground easily, it is a valuable plant.