Greetings from PDN to gardeners around the plant world. We’ve finally been getting some heat over the last few weeks so our bananas and elephant ears are finally growing. Once again, we left our Colocasia gigantea ‘Thailand Giant’ clump in the ground over winter and is has returned and is now over waist high. The secret to overwintering these seems to be covering the main growing point with a foot of shredded leaf mulch. I know I said we were having heat, but that’s NC heat, which is nothing to compare with the poor folks in Texas or Arizona. Garden writer and plantsman Greg Grant sent me a photo of his thermometer that hit 115 F, last week in east Texas. Gardeners in the Northeast and some parts of the Midwest have conversely seen much cooler than normal temperature with many cold high temperatures records being set.
We’re in the final stages of readying the 2009 Fall catalog and part of that annual process is reducing the size of our mailing list. This is done when our computer automatically eliminates anyone who has not placed an order in the last two years. Obviously, we don’t want to delete you if you would like to remain on the mailing list, so we have a special designation that allows non-customers such as garden writers, neighborhood gardening gurus, or folks who otherwise are fans of PDN and help promote the nursery. If you fit into this category and don’t always purchase every couple of years, please let us know so that we can code you correctly to keep you on the mailing list. If all goes well, the fall catalog supplement should go in the mail during the first week of August. In the meantime, we’d love for you to join us for our Summer Open House. We’ve just finished the first weekend and would love to see you join us this weekend for our final Open House until September.
As I work in my garden this summer, one of my annual chores is to examine the increase of shade throughout the garden. So often, we don’t notice the gradual decline in plants growing in a shade garden until the plants have shrunk to nothing, or in extreme cases, died completely. This decline is due to several factors, including a lack of adequate irrigation, and/or an increase in the amount of shade that is being cast by the trees above. Unless you are really observant, it is hard to imagine how much large trees grow each year. Since tree sizes aren’t static, it doesn’t take long for an area which has the ideal amount of filtered shade to become too dense for much of a herbaceous understory layer to survive.
First, realize most true woodland plants are spring ephemerals, meaning they get in their entire life cycle by the time the trees leaf out. In order to get plants that remain looking good in the woodland throughout the summer, we have to use prairie or woodland edge plants such as hosta and hellebores that will tolerate shade. There are very few of these plants that actually thrive in dense shade, including the likes of asarum, aspidistra, ruscus, and many ferns. To keep these woodland ‘interlopers’ happy, you’ll need to keep the canopy open so that filtered light can penetrate.
Try and train yourself to consciously watch plants whose size gets smaller each year instead of larger or whose growth becomes more spindly. The answer to the increasing shade is to raise the canopy of the shade by removing some of the lower tree limbs or to selectively thin the limbs. To keep a shade garden in good shape, this must be an annual process. I like to do this in late spring / early summer when I can tell how much shade a tree is producing after it has finished its spring growth flush.
Obviously, to remove limbs, you’ll need a good pole saw…either a manual or motorized type. I had always used manual pole saws like you find in the box or hardware stores. Several years ago, frustrated by the poor quality and lack of durability of these saws, I began researching to see if there was a better brand available. My research led me to Silky Saws. Silky Saws sell an array of high quality Japanese made pruning saws. For large overhead limb removal, I purchased a 21′ Hayauchi pole saw. To say the difference between what I had been using was night and day would be the understatement of the year. You’re not going to easily bend, break, or dull the blade with this baby. I had also been frustrated by never being able find a pole saw long enough to reach the tallest limbs until I bought my 21′ Hayauchi saw. After several years, I can still say this is one of the finest gardening tools I’ve ever owned. You can find these and many other great pruning saws at www.silkystore.com/ You’ll never go back to cheap saws again.
The other problem with woodland gardening is the amount of moisture required by large trees, which research indicates ranges between 50 and 200 gallons per day. If you aren’t supplementing your woodland garden with water, your herbaceous plants will suffer. Selective pruning as I mentioned earlier will also help to reduce the amount of water that the large trees require.
Many folks who visited this spring were concerned about the amount of winter burn on their agaves, after one of the coldest winters in more than six years. I explained that by summer, the growth rate of the agaves would render the damage as a distant memory and sure enough, visitors to our Summer Open House have commented on how good the agaves looked. Remember, the key to growing agaves is to keep them dry in the winter and grow them on a slope. In damp winter climates north of Zone 7, I’d recommend sinking four pieces of rebar around the clump in early winter and placing a piece of fiberglass (or similar material) atop the rebar. This works to keep moisture out of the crown in the winter months.
We always like to have a vigorous pollen exchange around the garden and this year’s target was arisaemas and agaves. We had very good luck with our agave x manfreda crosses this year as well as our arisaemas. We hadn’t made many arisaema crosses in recent years, but because our Arisaema fargesii x heterophyllum cross that we made nearly a decade ago looks so nice, we thought we’d try our hand again. Despite setting good seed on our crosses, there are many years ahead before we’ll be able to see these flower.
In our neck of the woods, this is the time to keep an eye out for seed production in the garden. In our part of NC, rain lily seed are produced rapidly after a rain and are usually ripe within a week of flowering. Rain lily seed are best sown fresh on the surface of the soil and do not store well. Arum seed are also ripening here, so if you don’t want critters spreading arums around your garden, now is the time to cut them off. I hope you’ve gathered your hellebore seed by now if you’re in the South or you’ll have a ‘ring around the lenten roses’ next spring. I recommend gathering the seed just as the pods begin to turn yellow and before they turn brown. Hellebore seed also germinates far better when sown fresh. The seed will be shiny black when ripe and can be surface sown (not covered) in a well-prepared soil bed or in containers.
One of the plant groups that is of great interest to us are hardy gladiolus. While virtually all of the recently introduced hybrids are bred not to overwinter, that is not true of many of the older hybrids. We have found several that are rock hardy here in Zone 7 and are hearing more and more reports of cultivars that are hardy as far north as Zone 4. We’d like to hear reports back from those that have purchased glads from us and have overwintered them north of Zone 7. We’d also be very interested if you have any other old glad that you grow which has also been cold hardy north of Zone 7. We already grow popular cultivars such as G. ‘Boone’ and G. ‘Dauntless’. I was very excited to speak with Dr. Neil Anderson of the University of Minnesota this winter, who is breeding (and having luck) growing gladiolus in Zones 3 and 4. We will be continuing to add more to our list since we find these both exceptional plants for summer bloom as well as for cut flowers.
In the nursery world, the recent big news is the sale of Yoder Brothers. Yoder Brothers is the country’s largest producer of chrysanthemums. If you’ve purchased a mum in the last few decades, it more than likely came from Yoder Brothers. Yoder has sold their entire mum and aster division to Syngenta Flowers of Switzerland, who will continue to produce and sell mums under the Yoder name. The old Yoder Brothers will continue to produce perennials and other crops under the name Aris.
I mentioned last month that plantsman Hans Hansen had left his long term job at Shady Oaks Nursery in Minnesota and I’m glad to report Hans has landed in Michigan at Walters Gardens, where he joins the likes of C.H. Falstad and Kevin Hurd as part of their plant breeding team. Walters Gardens, a large wholesaler, now joins Terra Nova as one of only a few perennials wholesalers with an entire team of plant breeders. There are a number of new plants in the pipeline and we look forward to watching them hit the market in the future.
In a surprise move perpetuated by the economic meltdown, the worlds authority on amorphophallus, Wilbert Hetterscheid, lost his job when Wageningen University in the Netherlands closed its botanic garden where Wilbert has been the Curator/General Manager since 2003. We were honored to have Wilbert visit PDN in 2006 to lecture on his favorite group of plants. Wilbert is looking at other options, hopefully within Holland, and will be relocating his amorphophallus reference collection. If you’ve been looking for an amorphophallus expert, Wilbert is your man. Good luck!
I also mentioned Southwest Native Seed last month and had forgotten that they actually do have a website now, so thanks to a reader for reminding me. Their website is www.southwesternnativeseeds.com
We were saddened to learn that rain lily guru, John Fellers of Alabama passed away on July 8 at the age of 87. John had probably done more research on rain lilies than anyone else in the history of the bulb world. His writings on the subject made a tremendous contribution to our wealth of knowledge including an upcoming article that will be published shortly by the International Bulb Society. Unfortunately, John never released any of his crosses to the commercial market.
For those who entered our Top 25 contest to compete for the $250 worth of plants, here are the results though mid July 2009. The list changes each month, so if your picks don’t show up near the top yet, don’t despair. There were only a few big movers over the last month, including Spigelia marilandica which jumped from 9th to 4th place and Allium ‘Millennium’ which jumped from 19th to 15th. We hope your choices are faring well as we countdown to the contest winner in December.
As always, thanks for taking time to read our rants and most of all, thank you so much for your support and orders this year!
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Thanks and enjoy