Strawberry Guava

[MarkP]

I presume that the original poster wants to preserve some native or otherwise desireable plants. That is part of the reason that I suggest the surgical strike route. It is also my experience that guava is extremely hard to kill and I have not read of much that will kill it in one go. I have read that roundup/glyphosate is relatively benign and breaks down quickly and would prefer to use it even if I have to use it multiple times. I have successfully suppressed yellow himalayan raspberry by hand pulling with very rare instances of using roundup and what makes it work is being persistant. The roundup just helps when the plant is too large to pull easily by hand due to the thorns. Now, guava is tougher but I still mantain that the key is investing enough time and energy rather than looking for that silver bullet.