Verbena

I bought a verbena plant at Elford Walled Garden a few months ago.

I put it in a pot and it grew taller and taller, like a tiny bloom on a stick. I wondered where I was going wrong. What should I have done?

Yesterday, at Rode Hall kitchen garden, they had a huge row of them. Just like mine, they were tall and gangly.

Mine bends over though.

Any helpful tips, my blipfriends ?