Happy first day of spring! I know many parts of the country are still covered in snow, but at least the calendar now makes it official. It’s been a roller coaster late winter as we opened for our Winter Open House to 70 degrees F, followed the next day by 36 hours of rain, then 2″ of snow, then consecutive lows of 16 and 15 degrees F…then back to 70 degrees F. How would you like to be a plant? Unlike humans, who can go inside on bad weather days, our plants are stuck to fend for themselves…pretty impressive, if you think about it. On the good side, this has been the first winter in six years we’ve gotten meaningful hardiness data on many of our trial plants…especially agaves.
Damage on agaves may take more than a month to show up after the plant has been affected by cold, so don’t get too excited when your plant looks great the morning after. Conversely, don’t fret over the older leaves turning black, as this is normal. The older leaves on an agave lose winter hardiness, while the new younger growth remains fine. Although I haven’t been able to confirm our theory, it appears the sugars (plant antifreeze) produced in the leaves tend to migrate from the older to the newer growth, leaving the older leaves more susceptible to winter damage.
We are also trialing a number of clumping bamboos including many in the genus borinda. All of the borindas have lost their foliage at 9 degrees F, including B. boliana which showed absolutely no damage at 12 degrees F, and despite West Coast reports of 0 degrees F tolerance without leaf burn. All plants in the genus bambusa also lost their leaves, but this was expected based on past experience. It will take a few months to determine if any of these will resprout from the canes or if they will need to be cut to the ground.
We’ve had several folks ask how our Wollemia nobilis fared in the cold this year, and the answer is fine. One plant showed a bit of foliar damage, but the other ten or so we’ve planted are untouched. The big problem with Wollemias is excess summer moisture, so be sure your soil drainage is impeccable. We’ve seen extensive foliar damage this winter on plants that haven’t shown any in recent years, one being the hardy cycads. Both C. taitungensis and C. panzhihuaensis had complete leaf frying this winter, but both are fine at the base and will resprout in late spring. I like to leave the damaged leaves until the new leaves begin to emerge, but that’s strictly a personal preference.
We’re actually having a very late spring as some plants are more than a month later than normal…which is a good thing. That being said, we’re in that time of year when other plants insist on waking up too early, followed by more cold weather. We’ve already had several days in the 70s this winter and sure enough, here come the early emerging Arisaema ringens out of the ground. That would have been fine if our temperatures hadn’t decided to drop back into the low teens. Podophyllum versipelle also peeked it’s head above ground, but we expect it to get blasted at least 2-3 times each spring. To deal with early emerging plants, we use spunbound polyester row covers we cut to fit over each plant. The plants are covered with the row covers, then topped with a large container. Row covers vary in their thickness and consequently their amount of temperature protection. Typically a 1.5 ounce fabric provides 6-8 degrees of protection while 3 ounce material provides 10+ degrees of protection. Even the best row cover isn’t much good below the mid-20s F. If you have the option to throw some shredded leaves over the row covers, that will provide added protection. The covers should be removed as soon as the weather permits. We store the cut row cover pieces during the summer so that they can be reused…many for over a decade.
We added a few special plants to the web right before open house including some of our special Arum italicum seedlings. We have been growing these from seed to select special forms, then subsequently propagating our selections by division. In doing this, we wind up with far too many excellent seedlings that aren’t unique enough from each other to introduce them all. This year we decided to offer these as a seed strain we call PDN Clouded Forms. They are different from the typical Italian arums in that instead of having marbled vein patterns, they have a silver center often flecked with green. At Open House this winter, I had a couple of folks comment about their arums spreading by runners to other areas of their garden. This is an oft perpetuated garden myth, since arums, like me and my bad knees, have no ability to run. When arums are allowed to set seed, birds can pick up the seed and deposit them anywhere throughout your garden. This is the only way arums can spread. If you get to the point where you have enough arums, simply cut off the flowers or developing seed between the time they flower in early May and the time the seed ripens in July. We hope you enjoy some of these special selections.
Related to arums is probably the strangest plant we grow, a plant known by the monikers, Pigs Butt Arum or Dead Horse Arum…Helicodiceros muscivorus. This unusual Mediterranean native emerges in late winter and flowers in early spring before going dormant for the summer. The three-dimensional foliage is strange enough, but the flowers that resemble (and smell like) a pig’s rear end, are truly bizarre, making a great gag gift for your gardening friends or a perfect way to get a non-interested child to pay attention to plants. We’ve only got a small number available this season, so get them while they last.
One of the plants I seem to continually talk about in spring is ipheion and the related nothoscordums. If you haven’t grown these, they are small bulbs that make a stunning late winter/early spring show, then go dormant in the summer. This year, we are offering for the first time, the white flowered Ipheion uniflorum ‘Greystone’ from NC’s Norman Beal. I. ‘Greystone’ has smaller flowers than the white flowered I. ‘Alberto Castillo’, but makes a much more compact clump and for us has had heavier flowering. Nothoscordum sellowianum (used to be an ipheion) makes a short 1″ tall fast offsetting clump topped, starting in February, with small bright yellow goblet-shaped flowers. Unlike most nothoscordums, this one is sterile, so you’ll need to divide it if you.d like to share. We have this growing in our full-sun rock garden and I can’t say enough good things about this gem.
As we head into spring, we routinely check our garden soils for nutrient levels and soil pH. Before we mulch, we prefer to add any soil amendments if needed. If our soil needs phosphorus, we use rock phosphate and if the soil need potassium, we use Greensand…a natural source of potassium. If you need to raise the pH of the soil, either calcitic lime or dolomitic lime will do the trick. If our soil test shows a high magnesium reading, we opt for calcitic lime. If you garden in an area with a high pH that you need to lower, then Flowers of Sulfur will do the trick. Once these are applied, then you’re ready to mulch. Timing of mulch application can be a real time saver for weed prevention. There are basically three groups of weeds; winter annuals, summer annuals, and perennials. Mulching isn’t of much use in preventing perennial weeds, but it can work wonders for many annual weeds…especially if they require light for germination, which many do. Some winter annual weeds start germinating in fall, while others germinate best in late winter. Two most popular annual weeds in our climate are chickweed and henbit. A good mulch applied before they sprout works wonders on their control.
We’ve been asked by a number of customers to compile a list of plants resistant to deer, since these have become the number one pest of gardeners nationwide. We’ve hesitated to put together a list because we don’t believe any plant is completely deer resistant and deer tastes, like human tastes, vary greatly. That being said, we spent quite a bit of time compiling our list from available research as well as observation from ourselves and our customers. Please keep in mind deer resistant plants may still get a nibble until the deer realizes it isn’t one of their favorites…even some humans eat things that many of us consider inedible…i.e. liver or tripe. Our list of deer resistant plants as well as a list of plants to attract hummingbirds have been posted in the article section of our website. We welcome your input on additions or deletions.
In the ‘in case you missed it’ category, you’ve got to check out the Floral Bras, compliments of the Quilters of SC that give a whole new meaning to sex in the garden. Actually, the bras will be on tour throughout South Carolina until fall, at which time they will be auctioned to benefit breast cancer patients. If you have a female gardener in your life who is hard to buy for, check these out.
Floral Bras to benefit breast cancer patients
In the ‘where are they now’ category, many plant collectors will no doubt remember Stephen Burns, formerly of the Vine and Branch Nursery in NC. Stephen was J.C. Raulston’s go-to grafter for the odd and hard to graft woodies in the 1980s. Stephen and his wife Rhonda closed the nursery in the late 1980s and moved to SC, where he worked for years at Gilbert’s Wholesale Nursery. From there, Stephen was called to the ministry, where he still works today.
The botanical garden world was surprised to hear of the impending retirement of Missouri Botanical Garden director Dr. Peter Raven, who announced he will be stepping down from his post at the end of July 2011. Peter has been the director at Mobot (as it is called in botanical circles) since 1971 (40 years in 2011). The news was such a surprise because most of us think of Peter as an ageless iconic figure that we all assumed would outlast the garden. Anyone with even a passing interest in plants has benefitted knowingly or unknowingly from Peter’s legacy of work. Peter’s devoted years to researching and publishing Floras of all the world’s plants including the current Flora of China project, which would probably never have happened without Peter’s vision and drive. Peter is married to the former Dr. Pat Duncan, an NCSU Horticulture Department graduate and former classmate of mine. You can read more about Peter and his list of accomplishments, awards, and philosophy at the links below.
Peter Raven at Wikipedia
Interview with Peter Raven
Thanks to David Theodoropoulos for alerting us to a great on-line seed germination reference. This publication from The International Board for Plant Genetic Resources is used by worldwide seed banks to assist them in germinating a wide range of unusual plants. This is not a homeowner guide, but one for scientists that requires a bit of seed germination knowledge to use properly and the information is amazing.
If you’re in the greenhouse or nursery business, you are probably too familiar with the Modine family of heaters, which are the top brand of heaters in our industry. When we got started in the business, we checked out other heating options, which at the time were limited to Reznor and from our research didn’t offer a dramatically better option. It wasn’t that Modine was a bad heater, but in greenhouse applications, the heaters didn’t have a very long life span, both due to the nursery moisture and fertilizer salt residue. I actually wrote to Modine several years ago expressing my concern and asking if they would work with us to develop a cover that would help protect the heaters in the summer when we removed our overwintering greenhouse covers. Unfortunately, they didn’t even choose to reply. After decades of going through a warehouse of Modine parts, Bob Stewart of Arrowhead Alpines told me about the L.B. White brand of Guardian heaters. The White heaters are actually designed for hog production and not greenhouse use, but the beauty is their use in hog production is far more degrading than in a greenhouse. Not only is the cost about half of a comparable Modine heater, but the operation is much simpler, the heat output is variable, and the heater is far more resistant to degradation in outdoor conditions. The White heaters are also ventless, meaning you will not need the standard heat losing vent stack that you typically see extruding from the greenhouse sidewall. If you live in an area where the temperatures drop below the 20s and the heater will run continuously, you will need a small intake and outflow vent since the heater can actual suck all of the oxygen out of the greenhouse and extinguish the pilot light. If you’ve been looking f or a different heater for your greenhouse, check out these heaters.
After 21 years, the Northwest Flower and Garden Show in Seattle and the San Francisco Flower and Garden Show, the second and third largest flower shows in the country respectively, come to an end this year. Salmon Bay Events, which puts on both shows, is for sale by founders, Duane and Alice Kelly, who are retiring from the flower show business so Duane can start a new career as a playwright. Attendance at both shows has declined in recent years due to the economy. The Northwest Show has just ended and the final San Francisco Show will be starting soon. If you’d like to attend the last show, check out the Garden Show website for more details. For between $1,000,000 and $2,000,000, the shows can be yours, so if you know anyone looking to buy a flower show, give Duane a call.
My speaking schedule for the remainder of the season has been updated. I look forward to meeting you when I visit your region for a program.
As many of us in the mail order industry struggle for survival, we’d once again like to say a heartfelt thanks for those who have ordered this year… Thank you!
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Thanks and enjoy