Good morning.

I am new to gardening and have two forsythia-related questions I'd
appreciate input on:

1. I want to place a 3-plant specimen grouping of forsythia in my
backyard, in the 4 to 6 foot tall range. What types of forsythia would
you recommend?

2. In doing a little web browsing, I've come across a couple of
attractive forsythia types that are "gamma-ray-induced mutations." Is
this practice common in gardening/horticulture? Is it controversial?

Thanks.