Planted new tree last month. It started branching out well, but the now hot weather is wilting the branches. Should I cut back now, and hope for the best?
Increase the watering and give the tree some phosphorus to help with root development. Newly planted trees are susceptible to heat stress and this is fixed by giving it more water.
My Myrtle tree is 3 years old. I pruned it this year to shape it. Now the leaves and branches are growing out, but they are dying and dropping off. What is wrong with my tree?
It sounds like you may have a fungus, though it is hard to say which one and many can cause this. Fortunately, all fungus can be treated with a fungicide. Treat the trees with a fungicide. I personally like neem oil as it will also treat for any pests the tree has and is safe for people and pets. Here is more information: https://www.gardeningknowhow.com/plant-problems/pests/pesticides/neem-oil-uses.htm
I pruned back my two trees in spring. Now the new growth is coming from around the bottom trunk of the tree. What do I need to do? This is the second year for both trees. The nursery said to not prune until the second year.
Just prune it off. They are suckers. It is likely that your trees are grafted and the rootstock is trying to reassert itself. You do not want this to happen as it will damage the scion (above part) of the tree as that is what you bought. This article will help:
https://www.gardeningknowhow.com/ornamental/trees/tgen/tree-sucker-removal-and-tree-sucker-control.htm
My neighbor has a beautiful crepe mrytle! I was wanting to take a cutting from it and start my own. How and when is the best time to do that? I was going to try to get a seed, but it had already dropped its seeds when I went over. What would be the best way for me to start my own without actually having to go out and buy one?
Here is an article that you may find helpful: https://www.gardeningknowhow.com/ornamental/trees/crepe-myrtle/how-to-propagate-crepe-myrtle-trees.htm
I have white spots that look like scales on the branches of two Red Rocket Crepe Myrtles. They have begun to get their leaves, but the ends of the branches left from last year have what looks like spider webs; and they are dead.
It sounds like it may might be tent worms. This article will help:
https://www.gardeningknowhow.com/problems/pests/tent-worms-tent-caterpillar-home-remedy.htm
My crepe myrtle has two stems entering the soil. I see additional little branches with leaves growing there. Should I remove them?
It sounds like you may have suckers. This article will help: https://www.gardeningknowhow.com/ornamental/trees/tgen/tree-sucker-removal-and-tree-sucker-control.htm
How do I shear a Crepe Myrtle?
These articles should help:
https://www.gardeningknowhow.com/ornamental/trees/crepe-myrtle/best-crepe-myrtle-pruning-time-when-to-prune-crepe-myrtle.htm
https://www.gardeningknowhow.com/ornamental/trees/crepe-myrtle/pruning-crepe-myrtle-trees.htm