Helianthus lemon queen perennial sunflower

Question

I planted these in my community garden plot a couple of months ago. They are about 5 feet tall which is great but I didn’t realize that they can be invasive. Also I didn’t realize that they don’t bloom for 2 years.
Questions:
(1) Are the roots invasive or only the seeds? If I dead head my flowers will that prevent invasiveness?
(2)Does it really take 2 years to bloom? I planted them because they are multi branched and I hoped to get flowers quickly

Thank you so much!

Answer 1

Truly unhybridized perennial Sunflowers do not seed all that well. This means that they tend to have a very aggressive root system, so unfortunately, keeping them deadheaded will not stop them from spreading.

As far as how long it takes them to bloom... They tend to take longer than their annual counterparts. This is a good estimate to see your first flowers.

Here is an article that will outline the differences between the annual and perennial Sunflowers: https://www.gardeningknowhow.com/ornamental/flowers/sunflower/is-my-sunflower-an-annual-or-a-perennial-sunflower.htm

Answer 2

Thank you BushDoctor. Great information! So are you saying that the Lemon Queen is a true unhybridized perennial sunflower? What about a hybridized perennial. Will it also have an aggressive root system (although maybe not AS aggresive)?
It seems I may have to pull the plants I have (2 of them), if I don't want to deal with spreading roots. I wish this had been on the seed packet!