I have two thornless blackberry plants in wooden pots. the post have several 1" holes drilled on the bottom for drainage and for the roots to decend. There are also rocks at the bottom for drainage. The problem is that the edges of the leaves are turning brown. I have read conflicting information about too much water and not enough water. I have feed them but they were brown before that. One of them has new growth. I dont want to lose them. I live in the southeastern corner of Arizona but the plants said heat tolerent.

Here's my experience: My thornless blackberry plants LOVE water, even more than the raspberries. They are in the ground though, and I water them at night, when needed, to let the water soak in overnight. Essentially, I don't let the blackberry bushes dry out.

I used to live in AZ, and I'm thinking yours are getting too much sun and not enough water. They may be heat tolerant but I wouldn't push it with full sun all day. Maybe behind a pillar, or under a tree, or porch area would be best for the pots.

Would you be able to upload a photo of the plant you're worried about? That way we could confirm if my thought is correct.

Thank you I'll try to upload a photo.

Well, blackberries grow wild in the Pacific Northwest. If you take that as a starting point, I'd say you're really pushing the zone trying to grow them in Southeast Arizona. So you're going to have to help them out a lot. First, are the pots big enough? These get to be quite large plants. Insulating the pots so the roots of the plant stay as cool as possible will help.

Try placing them where they will get only morning sun, and will be shaded in the afternoon so they don't get too hot. Water them thoroughly in the mornings and again if you can after they are in the shade in the afternoons. I agree with Alyssa, I don't think you can overwater these plants where you are. Spraying the leaves with water wouldn't hurt either. They are native to a place with much cooler temperatures than AZ and lots of rain. If you want them to grow and be happy, you're going to have to try and make them feel at home.