Q.Blackberry plant
Planted 3 weeks ago. Have some new growth but leaves turning yellow and end of beaches turning dark…looks dead. We have had a lot of rain in last month. What should I do? Is it blackberry calico?
Thx ch

Make sure the planting soil is good loamy soil and that the soil is not soggy.
Roots that sit in soggy soil will certainly rot. Your plants may have suffered root rot.
You can trim away the dead plant material and access the planting location and soil conditions.
This article will help you.
https://www.gardeningknowhow.com/edible/fruits/blackberries/growing-blackberry-bushes.htm