container gardening

Question

What size container is needed for one penstemon?

Answer 1

Pot size will depend on the size of perennial plant that you start with. If you purchase a starter pot--example a 4 to 5 inch pot size, you can go ahead and plant the Penstemon in a 8" pot.
You can sometimes locate larger potted Penstemon and you would pot up them about 1 size larger then the existing greenhouse pot.

https://www.gardeningknowhow.com/ornamental/flowers/penstemon/penstemon-beard-tongue.htm