I posted a message on the CP listserv about some strong growth I've been seeing in my Drosera hamiltonii and one of the PFT moderators (Tamlin) invited me over here to share how I was growing them.
First a bit of background. I'm in Victoria, Australia. I grow most of my plants outdoors without any covering. Temperatures range from around 0 to 45 degrees Celsius. Most of the Drosera get lightly filtered sunlight. I first tried growing D.hamiltonii around 5 years ago with little success. They were grown in 2:1 peat and sand and watered by tray. Despite the books saying this is an easy species my plants grew OK for a while but quickly went downhill in the cooler months, never growing bigger than an inch. They possibly fair better in the more controlled environment of a terrarium or greenhouse compared to outside.
About 2 years ago I decided to give D.hamiltonii another try using some techniques that some Australian growers have successfully used for Cephalotus. D.hamiltonii grows in the same area as Cephalotus so I figured it might appreciate the same conditions. I'm basically keeping the plant drier than before but still giving it a constant supply of water. As a result my plants are now putting out strong growth with rosettes reaching diameters of 3" as opposed to 2" mentioned in most books. The plants are grown in a similar mix to my first plants (around 2:1 to 1:1 peat and sand). The pots (I'm using 4") sit in a tray filled with fine pebbles so the plant is sitting on top of the water rather than in it. This way the mix doesn't get waterlogged but the plant still has access to water. The mix in mounded up above the top of the pot and the plant is planted into the top of the mound. The height of the mound is around ½ to 1X the height of the pot. Richard Davion from South Australia recommends this technique for Cephalotus so I thought it was worth trying for D.hamiltonii. What I think is going on is that I'm lowering the water table within the pot so that the upper portion of the mix stays fairly dry but the roots can still reach an adequate supply of water deeper in the pot.
I'm not recommending this as a technique for everyone but it does seem to work well in my conditions. I don't know how this technique will work in terrariums or greenhouses or in other climates. As I mentioned my D.hamiltonii rosettes are now reaching ~3" from leaf tip to leaf tip. These plants were obtained from a reliable nursery and the local Drosera growers have no problems with its ID so I'm quite confident that what I'm growing is D.hamiltonii. I do not believe it is any type of 'giant' form. I'd be very interested to hear from anyone who has plants of similar size. I'd like to know whether this technique is producing abnormally large growth or whether the size of my plants is not uncommon and what is printed in the literature is indicative of 'average' plants not the plants full potential under normal conditions.