Sadly for all of us watergardening enthusiasts at Duke Gardens, another growing season has officially come to an end. During the last week in October, we dismantled our display ponds, which required some heavy lifting and "grubby" work as our volunteer John Wyman likes to describe it.Our beloved Victoria waterlilies were transferred (carefully, and with the aid of thick gloves and pitchforks) to the compost pile, while our hardy waterlilies were lowered to the pond bottom to slumber peacefully until Spring.
We then uprooted all of our tropical waterlilies and sifted through the muck and roots to find any tubers they produced over the summer months. It was a bit like a treasure hunt, though unfortunately we did not come out of it with a rich assortment of tubers. Of the tropicals that did not produce tubers, our favorites were potted in 6" round pots and transferred to our heated greenhouse tubs where we will try to coax them through the winter.
This method of saving plants from year to year is not ideal since it takes up much more valuable greenhouse space then do the tubers. In talking with other growers, including Joe Tomocik at Denver Botanic Gardens and Tim Jennings at Longwood Gardens, we will be working to increase our tuber production by growing some plants of each hybrid in 4" pots throughout next summer with minimal fertilization. The combination of small pot size and a lack of nutrients should force the plants' survival mechanisms to kick in, resulting in a much higher percentage of tuber production.
Another problem we have had for the past few seasons relates to the fast growth of our Victoria lilies. These little monsters have a very healthy happy appetite and an incredibly rapid growth rate. We have plenty of surface area available in our ponds and strive to grow the largest plants we can. The only problem is, as the plants grow, they actually push themselves upward and out of the water. This year, we had one Victoria grow so quickly that the crown of the plant was out of the water by mid-July! Since we grow the plant in this particular pond in an area of water that is 4.5' deep, we are forced to use a metal stand to keep the plant's container at a good level in the water (about 12" from the surface) that makes it easy to maintain and fertilize. However, once the crown is exposed to the hot summer sun, the new leaves and blooms quickly begin to dry up and die.
Long story short, we were forced to make a decision this summer - either leave the plant to die a premature death, or assemble a team of volunteers to help lift the pot from the stand and place it onto another pot filled with gravel on the pond bottom. We chose the latter, which made fertilization at the end of the season impossible without diving equipment, but luckily the plant didn't seem to mind too much and we were able to enjoy its presence in the pond for another three months. After talking with Tim at Longwood, I learned that they have had the same problem with their Victorias, and they actually pot their plants at the bottom of a deep pot and add soil throughout the season as the crown grows upward. We will definitely be using this trick next summer, and it will eliminate the need to purchase scuba gear to fertilize future plants - a win-win situation!
And now the long months of winter begin, leaving us with plenty of time to plan for next year. We hope to expand our collection of aquatic plants, and would especially love to add some of the beautiful Australian waterlilies to our collection. In the meantime, we will have to settle for admiring the fragrant blooms of winter-blooming water hawthorne and the evergreen foliage of sweetflag and horsetail rush to get us through.
A special thanks to the oustanding crew of water garden volunteers pictured below (John Wyman, Karen Webbink, Jeff Prather, and Jean Reniers) for making 2009 another excellent season at Duke Gardens!
Photo provided by Larry Nau.
