I will try to give measurements sometime this week. My plants grew a lot since the last picture I took on 6/4. My tallest plant right now looks like one of the Bott's Strain. The American Giant Hybrid looks like a close second, but it is by far the largest overall plant with the largest leaf size, stem thickness. At my mom's house in NY, my Kongs are by far the largest. I've found that you can't alawys go by their growth in the beginning. I grew three Craven plants in 2002, and the one that I thought was going to be the tallest, ended up being the shortest. The one that I thought was going to be the smallest ended up over 15 feet tall.
I took some pictures, but I have to transfer them to the computer. It probably won't be until next week sometime. I'm heading off on a fishing trip tonight. Anyways, my tallest plant was Bott's Strain at slightly over 4 1/2 feet. So far, the Bott's Strain don't have your standard Mammoth Russian look to them. They don't seem to have large leaves or stems, but they are all very tall. I'm a bit concerned that they may blow over easily in a storm. The largest overall plant was American Giant Hybrid which was 4 feet tall, 11 inch length & width on the largest leaf, and a 4 inch stem circumfrence. My Craven, Diane Strain, and Hemker plants were planted later; so they are smaller, and it's still early to judge how they are going to do.
What is the latest in the season you can plant sunflowers, such as the craven??
Last year someone knocked down all my sunflowers in my mom's driveway; so around the end of June I planted some standard Mammoth Russians (Agway brand) in their place. By the time fall came, they only grew to 5 feet at the most. They flowered and set seed, but were unable to grow to the maximum potential. Craven has the longest growing season I've seen from any variety; so you should plant it end of April/Beginning of May. If you want a really big plant, I would avoid planting any later then mid-May.
Thanks for the reply!