"New"
is understandably relative when talking about new tree varieties,
I think you'll agree. Whereas some wholly unnecessary, black-and-orange,
double-hung tulip should rightfully be considered old-hat its
second year out of the gate, fabulously hip trees developed for
our northern climate easily retain the "new" label
for at least a decade, so says I.
That's why I'm featuring Cercis candensis 'Minnesota Strain' — Minnesota Redbud — in this week's New From the U.
This spreading tree is native to areas of the United States south and east of Minnesota, but with variable winter hardiness, few large specimens grew in Minnesota prior to development of the 'Minnesota Strain' variety, a project the underpaid University of Minnesota Master Zen Tree Geeks started working on in the 1960s. In 1992, the U allowed 'Minnesota Strain' out of the bag, and into the commercial market.
And lordy, what a tree it is. Redbud may be the perfect ornamental.
In bloom, it is the most spectacular plant you could ever see, rivaling tropicals for bash and sass. The dark pink/purple flowers this hummer unleashes in early May (prior to leafing, like some magnolias) will draw the attention of every neighbor, stranger, and local newspaper photographer in your town.
The tree tops out at 12 feet, meaning you've got a spot for one whether you live in the city or countryside. It has an open-spreading, multi-stemmed habit that gives it an architectural/sculptural presence all year 'round.
Why the 'Minnesota Strain' Redbud is not more popular in the nursery industry is unclear, although the tree has definitely been getting more word-of-mouth in the last two years. People who have one can't say enough about them.
The tree prefers full sun but grows and blooms quite well in part shade.
Of course, perhaps no tree is truly perfect. It's hardy only to Zone 4, I'm afraid, meaning I've just spent two minutes dashing the hopes of all you fine visitors from northern Minnesota, and the Zones 3 and 2 elsewhere around the world. I'll see if I can't find a small ornamental tree almost as spectacular to write about, in the seasons ahead.
Ooh, ooh … this is a real scoop, and I'm not kidding. Probably less than 100 people in the nation know what I am about to tell you.
The "Maxi-Mum," the University of Minnesota's entrant into the Plant Freak of the Century competition, is no more. Kaput. Finis. See ya.
In name, at least.
Ball Seed Company just bought all rights and patents from the
U., and are burying the Maxi-Mum moniker. I was not told the
new name, but Ball will mass-produce and bring it back into the
nationwide market next season. I don't know if 'Betty-Lou,' the
one cultivar released by the U., will retain that name, either.
In case you're not from around these parts, the Maxi-Mum is a giant, shrub-like mum developed over the past ten or twenty years at the St. Paul campus. The thing gets four feet high, with an equal spread, pure Chrysanthemum (I refuse to say Dendranthema) through and through.
This is cool for the U. It means big-time bucks, a major score, and the folks at the University's 70-year-old Mum Project are to be commended, because this type of sale creates funding for years to come.
Now if we can just work toward developing true hardiness with what we have, instead of always laboring under the assumption that bigger is better. I need a four-foot mum like I need another 80-year-old oak.
Perhaps this week it should be what's new AT the U: for the first time in over 10 years, the University of Minnesota has raised the rates on soil tests, the cost for each test rising from $7 to $10, effective last week.
Everyone who gardens should test their soil periodically to monitor the soil pH, phosphorus and potassium levels, soil organic matter content, and texture. Taking the test is simple: collect soil samples from five spots in the garden or lawn area, mix them in a clean container then mail or UPS about two cups over for testing.
This is a great service for people in rural areas, and many gardeners send samples in to the University of MN from states other than Minnesota. We might cheat at basketball, but we NEVER cut corners when it comes to evaluating your hard-earned earth. Best damn soil-testers in the world, right there, at the St. Paul campus.
The soluble salts/excess salts test remains at $5, and the lead test stays at $15, to save you all from e-mailing me.
Forms are available for download from: http://soiltest.coafes.umn.edu/howtosam.htm.
If you're visiting this site from outside of Minnesota, you probably missed this whole 20-Mule Team Borax/creeping charlie thing that's been going on the last five years. Lucky you.
Creeping charlie is the astonishingly perennial "weed" that invades lawns across our state, much to the consternation of otherwise level-headed Minnesotans. Here I am, volunteering four hours of my time on a Saturday afternoon in June, manning the Master Gardener table at a Home Depot, of all god forsaken places, ready to help people choose groundcovers, teach them how to pinch annuals, explain how to prepare soil for rhododendrons, and ninety percent of the questions I get concern ways to get rid of creeping charlie (and does Borax work?).
Look fella, what's the matter with creeping charlie? It blooms a pretty blue about half the season, spreads like mad, grows in sun to part shade, hardy to Zone 1, can't get enough of water, laughs at drought, you can mow it, bury it, divide it, transplant it, and the only thing it will not do is die.
I always contend the nursery industry was asleep at the switch on this one. There's a parallel universe somewhere, where creeping charlie is sold in flats as a groundcover, and a pricey one, at that. It's been hybridized over and over so that new cultivars have been released that bloom in lavender and pink and rose, with names like Creeping Charlene, Stealth, and Charlie's Pride. Perennial Plant Association 2005 Perennial of the Year: Creeping Charlie 'William Shatner.'
But anyway, people hate it. So for a while, the hot remedy for creeping charle was to mix Borax with water, because some gardener in Hastings told the local paper he'd wiped it right out with the stuff.
Well, researchers at the University of Minnesota have concluded that a) done just right, the Borax Solution can control creeping charlie and b) there's enough of a downside to the concoction that they no longer recommend its use.
In minute amounts, boron (the active ingredient in Borax) has a toxic effect on creeping charlie. But it needs to be applied with extreme precision and care, because boron remains immobile in soil, and can quickly accumulate to form a "hot spot" in the lawn, i.e. a spot where nothing grows, including grass.
So the University says, if you try the Borax bit, you can only do two applications per year, for two years, and no more after that. Well, you're not going to knock out creeping charlie with two measly applications in two years. The formula and theory always did have a bit of a Jerry Baker ring to it.
Much better to use real, approved, deadly chemicals made by evil white males employed by major, Republican party-contributing manufacturers, bomb the stuff four times a year (late fall is the one not to forget) and keep on 'er until the accursed weed is gone, gone, gone.
Or, do as my next-door neighbor does. He's been conducting an experiment on Creeping Charlie In The Massive, Rolling Lawn, since the day I moved in. So far as I can tell, it involves doing nothing about it for fifteen years, then seeing what happens.
Talk about university
research making an impact on the world — in 1993, scientists
at the University of Minnesota developed CM6, a robot that could
pull weeds and open a beer bottle. No, CM6 was actually
an agent (whatever that is) to help seeds better germinate in
cold soil.
They started testing it on soybeans, and test results show that CM6 increased yields by five to ten percent. That might not seem like a lot, but think for a minute how many extra soybeans you get when you increase billions by five percent.
What they found was the seedlings from CM6-treated seeds developed a larger rooting system, which helps plants tolerate more stress, say from late spring frosts or overall cool temperatures after planting.
Next they moved on to corn, and plan to have a go at vegetables grown in northern climates.
Plants grown from CM6 seeds retain an increased hardiness tolerance. I'm hoping they'll eventually get around to shrubs and perennials, where CM6-treated plants could be developed enabling gardeners to grow Zone 5 stuff in Zone 4, Zone 4 in Zone 3, and so on.
Taken to the extreme, it means that some day, we northerners might have more than a couple choices for growing a proper deciduous hedge!
The project time frame extends through 2001, and is headed by Paul Li of the Horticultural Science department at the University of Minnesota.
Studies at the University of Minnesota have found little difference in the level of phosphorus in storm runoff water when comparing areas using lawn fertilizers with phosphates versus areas where phosphates are not in use.
What contributes most to excessive algae growth in lakes? Grass clippings, leaves and other plant debris left in the street during rainstorms. These organic, high-phosphorus materials get washed into the street drains and wind up contaminating lakes and rivers.
Fertilizer containing phosphate does its harm when homeowners fertilize too closely to the street, don't close the hopper when turning their drop spreaders on the street, and keep it open over any paved area. It's a part of the problem, you bet. Applied correctly, however, lawn fertilizer is not the culprit many think it is.
If you are interested or curious about eutrophication, however, I encourage you to go this column for more information. Parts of it are pretty decent slogging.
Yard & Garden Line to the Rescue
The Yard & Garden Line isn't brand-new, but in its second season it's really a wonderful service that I want to be sure you know about. Have a question on gardening or landscape plants? Pests or tree health? Insects or wildlife? Soil testing or water quality? This service is indispensable.
It's all courtesy of the U of MN Extension Service, the same hard-rockin' horticulturists who looked the other way and somehow let me into the Master Gardener program. Just phone 612-624-4771 in the metro, or 888-624-4771 from greater Minnesota. You can talk to a University expert directly ($5), get help with wildlife questions from the staff at the Bell Museum of Natural History (free), discuss water quality with the Water Line Staff (free), listen to about a zillion mostly well-done INFO U tapes (free), learn how to submit plant, insect or soil samples ($5-$7), or leave a message for a call back from a Master Gardener (within 24 hours — usually the same day; always free).
Just dial the numbers above and the automated service will get you right where you want to go. Hennepin County Master Gardeners gave personalized answers to garden questions to over 5,000 callers last year in Hennepin County alone.
It appears that
two very popular apple trees developed by researchers at the
University of Minnesota have even more going for them than merely
producing fabulous-tasting apples.
New research by the U's Horticultural Research Center shows that the Honeycrisp and Zestar! varieties of apple trees are far less prone to apple scab and fire blight, the two prominent diseases that reduce to tears many hobby apple growers in our region each year.
The Honeycrisp, in fact, has been officially categorized as "resistant," a classification the University does not bestow lightly. Now if you can just find one at the nurseries. Demand is so high that getting your hands on a Honeycrisp to plant in your yard requires some calling around town, but you'll find one.
During springtime here in the north, it’s easy to forget about what it will take to have an attractive, colorful fall garden display. We get so wrapped up in the excitement of seeing color from spring bulbs, spring-blooming perennials such as Pulmonaria, Dicentra (bleeding heart) and Lamium, plus the wonderful displays of seductive, vibrant bloom granted by rhododendrons, azaleas and crabapple trees, that we sometimes zone out concerning our plans for ensuring plenty of color in our end-of-the-season escapades.
Enter Chrysanthemum in general, and the new varieties developed at the University of Minnesota in particular.
Now is the time to buy and plant mums, the standard-bearer for fantastic fall color. Maxi-Mums, as the newest breed of northern mums are called, are the result of literally decades of mum breeding at the University. The first release, ‘Betty Lou,’ is a striking red cushion-type mum with a massive habit-after just a few seasons, plants can reach heights of three to four feet, with an equal diameter. Quite a sight.
Plant mums now in Zone 4, in two weeks in Zone 3 and by June 1st in Zone 2. They do best in full sun, but I have good success in my less-than-full-sunny yard by ensuring that the soil is well-drained, the plants are fertilized three times through August 15th, and receive about an inch of water per week.
Pinch mums by literally pinching off half of each stem with thumb and forefinger, beginning now, again in three to four weeks, and once more on the fourth of July.
Last summer I heard
that new research from Iowa State University indicated garden
mums wintered better if left alone in the fall, i.e. not cut
down prior to covering with protective winter mulch.
I grow a lot of mums, and can't imagine a northern garden in the fall without them. I've always had pretty good luck over-wintering them, mainly because I buy good, quality mums from Dooley's Mum Gardens in Hutchinson.
But in the odd springs when I have finally had to face the fact that I've lost a perennial or two over the winter, it's usually this mum or that mum that gave up the ghost. So late last fall, while cutting my perennial beds down, I left all my mums up, tucking marsh hay around them instead of on top.
Two weeks ago, wow! The first mum I cleared hay from revealed a lush green patch of fresh new mum tips nearly a foot across! It was so impressive, I had to take a picture. My mums have never come back so strong in the spring.
So now we know. Full credit to I.S.U. — go Hawks (or is it Cyclones?). Funny thing was, I interviewed Vince Dooley (one of Minnesota's supreme mum experts) last week for an article I'm writing on mums for Northern Gardener, and when I asked Vince if he knew about this trick, he said of course, he's been growing mums in fields for forty years and never, ever cuts them down in the fall. When I asked him why he never told anyone, he said because no one ever asked him. You gotta love Vince.
By mid-April you should remove that rough paper tree wrap we've all gotten used to applying, ace bandage-like, around the trunks of young crabapples, maples, aspen and other smooth-barked tree varieties to help them survive our northern winters. Throw it on the compost pile, then never use the stuff again.
New research from the University of Minnesota has found that wrapping the trunks of trees is about the worst thing you can do when attempting to prevent cracking from winter sun scald. Even when applied properly, the paper traps moisture between it and the bark, the winter sun warms the outer bark just as dangerously as without wrap, and in most cases the tree wrap makes the whole situation worse, not better.
What does the Renegade Gardener do? Since the origin of tree wrap was the correct theory that the best way to protect a young tree's trunk from winter injury is to provide shade, I do just that. I use three, eight inch-wide cedar boards left over from a fence project. Each board has a sharp wooden stake screwed to it and coming out about a foot off one end. I make a nearly U-shaped mini-fence out of them, positioned six inches away from the trunk on the south, southeast and southwest sides of my one immature tree that still needs winter protection, a Red Sparkler crab. The boards are about five feet tall as they stick straight up from the ground, edges just touching, held securely in place by the stake ends, which I pound into the ground in the fall before the turf freezes. Instant, mildly attractive, winter-long shade for tender trunks.