Protecting plants from frost

What a difference a year makes.  This time last year our growing degree day accumulations were nearly a month ahead of normal and we had already experienced temperatures in the 80’s, with more than a week straight of 70 + deg.  temperatures.   This year, of course, is a different story.  But spring will come eventually.  As trees and shrubs begin to leaf out or we get antsy and begin to plant annuals, we need to be prepared for late frosts.

Searching on the internet for ‘plant frost protection’ will yield a wide array of strategies for reducing frost damage.  Some strategies such as frost irrigation or wind turbines are mainly geared to commercial horticultural operations such as orchards or nurseries.  Other techniques such as a various spray-on products usually provide only a few degrees of protection or are variable in their effectiveness.  For homeowners, the most effective technique is the ‘old tried and true’; covering plants loosely with a bed sheet or similar lightweight fabric.



When covering plants for frost protection it is important to remember the basic principle at work here.  Late frosts typically occur on clear nights.  That’s because the lack of cloud cover allows heat from the earth to re-radiate into outer space.  By draping a sheet or other lightweight covering over plants, the radiant heat from the ground is trapped, preventing plants from freezing.


I bring this up because I have seen several forms of ‘plant protection bags’ currently on the market.  In terms of protection from late frosts, these are more likely to turn out to be plant body bags.  Some of these bags are designed to gather at the base; sort of like putting on a coat. This is another example where making analogies between human function and plant function falls apart.


Remember, the point of covering plants is to trap the earth’s heat, not the plant’s heat.

More importantly, frost cover protection needs to be removed each morning as soon as temperatures begin to warm.  Late frosts usually occur on clear nights, which means the next morning is typically bright and sunny.   Under direct sun, temperatures under frost covers can build quickly, resulting in heat damage to new growth.  Yes, going out to drape sheets over plants each evening and then removing them the next morning is a pain but like so many things in life, the tried and true is the safest bet.

The Winter Weekend Garden Warrior

As Garden Professors, we are very careful regarding product endorsements. Actually, much energy is spent trying to bring to light weird/crappy/useless/money-wasting gardening products.

But when we feel strongly about the usefulness, quality, and utility of a product, it is our duty to pass that information along as well.

I didn’t mean to be a walking advertisement last weekend.

We were in the final throes of getting our garden cut back; Joel was laughing that I “needed another set of hands” when I came around the corner.  “Not with my fabulous Firehose Work Pants from Duluth Trading Company, I don’t!”  Thus the inspiration for this post.

All products noted are, variously: warm, waterproof, full of pockets, sharp, indestructible, dependable, and/or delicious.

The eternal [gardening] optimist

I’ve gotten better, actually.  After slaying hundreds of dollars worth of mail-order and/or inappropriate plants, I’ve learned to curb my urges a bit.

But not this time.

I was overcome by a sale at “Annies Annuals and Perennials” –  the most decadent, irresistible, West Coast, Zone 9 catalog ever.

Behold! The impossible-to-grow and majestic Puya*

Mine! Mine! Mine!
It will reside in my greenhouse over the winter.

Packing peanut left in pot for scale.

Now taking bets as to how many years ’till bloom. Side action on years/months until I kill it.

*Can one of you familiar with the genus inform me as to pronunciation? I’m pretty sure my current “rhymes with booyah” isn’t it.


Important, must-read announcement regarding pesticide use

There’s a new report out from the Weed Science Society of America (WSSA) which blasts a common piece of gardening advice: use least toxic pesticides only as a last resort.  Popular as it may be, this advice is not scientifically grounded and can actually cause more harm than good.  The WSSA is joined in this announcement by the American Phytopathological Society (APS) and the Plant-Insect Ecosystems Section of the Entomological Society of
America (P-IE ESA).

This is a must-read for anyone who is a responsible educator regarding pesticide use, which includes Master Gardeners and other horticulture paraprofessionals.  You’ll want to use the webpage link above to read the entire announcement, but here’s a paragraph to get you thinking:

“There is no benefit or scientific basis to simplistic messages like “use least toxic pesticides as a last resort” for the large number of pesticide users who apply pesticides according to the label and practice good stewardship. Nor are these messages beneficial for those who neither seek training nor adequately read the label believing instead that it is safe, practical, and effective to simply choose a product considered a “least toxic pesticide” and apply it only as a “last resort.” These messages hinder pesticide safety and stewardship education and practices that are in the best interest of the pesticide user, our food supply, public health and ecosystem preservation.”

Fall for Ornamental Grasses

I’ve written about ornamental grasses previously – they really are one of the toughest, most useful yet under-appreciated groups of garden plants.  Most provide at least three seasons of interest, but fall is when they really shake their pom-poms.

On a recent conference trip to western Michigan with pal and plantsman Paul Westervelt, we stopped by the trials at Walter’s Gardens of Zeeland – one of the largest perennial propagators (wholesale) in the country.

It was a beautiful, breezy day in their extensive gardens, and the grasses were positively alive with light and motion (and kittens – seven or eight, I think). What a fantastic afternoon.

 Here are a few recent introductions that knocked our socks off.  All are hardy to at least USDA Zone 5, heat tolerant to Zone 8 or 9, and the non-natives have been screened for any invasive tendencies. All are patented.

Panicum virgatum ‘Dust Devil’

 There are many great cultivars of our native switchgrass out there; but few come in under 6’ or 7’ – problematic for the small garden. Dust Devil is comparatively  petite – 3 to 4 feet tall, blue-green foliage, and resists the rain beat-down that often happens to the rangy cultivars. Selected by Michigander Gary Trucks.


Pennisetum alopecuroides ‘Burgundy Bunny’

 Paul and I were especially impressed by this sport of ‘Little Bunny’.  I’ve grown tons of ‘Little Bunny’ which is eminently useful for a pouf of “grassiness” at the front of the border.  ‘Burgundy Bunny’ brings terrific color that only gets better in the fall, in the same small package.  From Walla Walla Nursery and introduced by Plant Haven.

Paul models Pennisetum alopecuroides ‘Red Head’

Nothing petite about this monster Fountain Grass.  Wow. 5’ tall and as wide, with gigantic foxtail plumes. As with most Pennisetum species, the show starts mid-summer and continues through fall.  Selected by the perennially prolific Brent Horvath of Intrinsic Perennials.


Schizycharium scoparium Blue Heaven™ (‘MinnBlueA’)


Selected by grass maven Dr. Mary Meyer from her trials at the University of Minnesota.  Mary has found a nice Little Bluestem that has outstanding foliage color (gets even better as the season progresses) and a very upright habit that fights the flop.  Native across much of North America and perfect for awful sites, Little Bluestem laughs at clay, heat, and drought, once established.  

 Andropogon gerardii ‘Indian Warrior’

Little Bluestem’s big brother of the tall grass prairie.  Another upright flop-fighter, this Big Bluestem is from Brent Horvath/Intrinsic. I’ve enjoyed Andropogon in my garden (got it from Paul) – the colors are amazing- but by summer’s end, they’ve flopped all over their neighbors. Can’t wait to give ‘Indian Warrior’ a try.

Lots more info on these and other grasses and perennials at Walters Gardens’ consumer portal


Kittens in the grasses.  Ahn.


Finally: when in Grand Rapids, stop by HopCat for a tremendous selection of Michigan craft beers and hard ciders and the suitably-name Crack Fries (yes!!!). 

Grow Something Rude and Smelly!

Tired of
Tradescantia? Sick of Stachys? Exhausted from Echinacea?
Stick THIS in your border!

Dracunculus vulgaris
  at the Hahn Horticulture Garden, Virginia Tech. Hardy to USDA Zone 5b.

Closely related (as one might imagine) to
Amorphophallus. Lovely silver-splashed foliage, velvety crimson spathe, and big honkin’ spadix in early summer.

Easy to grow; part shade and good drainage seem to work well. After a few years, you’ll have several offsets to share with your dearest friends/worst enemies.

At the peak of bloom, the fragrance is reminiscent of lily or tuberose (if they were arranged on a patty of rotting hamburger).

Garden Interns Brittaney and Anna think it’s JUST FABULOUS!

Available from that purveyor of all plants phallic, 
Plant Delights.
(They have lots of other stuff, too.)

Truth in advertising, finally.

*drum roll*

Ladies and gentlemen, the latest effort in pinto bean breeding from Seminis Vegetable Seeds:

"beans, beans, good for your heart..."


Windbreaker is an upright, short-vine pinto bean that has produced consistently good yields, especially for the Red River Valley production area. Windbreaker ripens quickly and uniformly with reduced seed weathering. Try Windbreaker in narrow rows for direct harvest.
Relative Days to Maturity: 94-98
Plant Type: Indeterminate, short vine
Color: Brown flecks on buff
Seeds/LB: 1,076
Disease Resistance: BCMV, R (R)

Happy Friday

Oooof, what a week. End of the semester, quizzes, labs, hosting of faculty position candidate, Hort Club Plant Sale, and 2 graduate student defenses in 8 days (3 in 15 days – am up to my pits in theses 😉

Sorry to say, I’m not feeling particularly profound or informative (like that ever happens), but I do have gardening fever! We’re so close to our last-frost date I’m ready to barge ahead with putting out warm-season veg, tropicals and annuals.

Happy end-of-the-semester to my fellow GPs – hope you have time this weekend to dig in the dirt.

And to all our readers, thank you for sticking with us throughout this crazy spring despite slightly erratic postings.

Now get out there and GARDEN!

Rules, guidelines, and to-do lists

Elizabeth: You have to take me to shore! According to the Code of the Order of the Brethren…

Captain Barbossa: First, your return to shore was not part of our negotiations nor our agreement, so I ‘must’ do nothing.

And secondly, you must be a pirate for the Pirate’s Code to apply, and you’re not.

And thirdly, the code is more what you call "guidelines" than actual rules.

Welcome aboard the Black Pearl, Miss Turner!

—  Pirates Of The Caribbean: The Curse Of The Black Pearl

There are ways, and then there are ways.

I’m always torn on this topic when it comes to pirate…I mean, gardening. How much I consider “rules” is minimal.  There are few absolutes.  Guidelines? Yes. Lots.

I know, absolutes and rules make decision-making easier and life simpler. Do this, now. Don’t do that, you’ll kill it.

Novices (at anything) especially appreciate rules.

As a not-so-seasoned beekeeper, the wildly diverse range of opinions and conflicting information on any one point is making me nuts.  Plus, all direction seem to come with the unspoken sentiment “…or they’ll DIE”.  March comes…”feed a 1:1 syrup to ensure a strong brood before nectar flow." Just as popular: “do NOT feed syrup in the spring, the bees have to exert too much effort to evaporate the water out and the hive will be too humid (and then you-know-what happens).  Aargh

To-do lists: great suggestions or fun-crushing obstacles to gardening enjoyment?

As the seasons change, you can’t pick up a gardening magazine or read a local paper column without some mention of Things You Would Be Doing In Your Garden Right Now If You Were Worth A Damn. Some lists even use the term "chores."  Chores are splitting wood and cleaning the toilet. Gardening, though requiring physical activity, is not a chore. Back to lists: a very fine regional gardening newsletter I just received had no fewer than 32 items on their March-April "To-Do List".  Thirty-two.

Three to-do directives I’ve seen in the last month and my judgement thereof:

“Browse plant and seed catalogs and get your orders in.”  Duh. Rule.

"Don’t prune Buddleia and other sub-shrubs until the buds are breaking. If you prune it in the fall, it will DIE."  Guideline.  I’ve done both, with no fatalities (has anyone actually killed a  butterfly bush by accident?).

“Wait until after last frost to set out tender annuals and warm-season vegetables.” I think our last frost was sometime back in February. Every man for himself on this one. I’m shooting for tomatoes in May.

Some lists skew more towards hard labor while others are not so time-consuming – such as “cut some daffodils and bring them inside to enjoy!” Marvelous! I may actually get around to that!  But wait – there’s a caveat – “because daffodil sap is ‘toxic’, don’t mix any other species of cut flowers in with them."

[or they’ll DIE]

Madison Wisconsin takes care of bees-ness

The bee blogosphere (hiveosphere?) and listservs were abuzz the past two
days with news that Madison, Wisconsin, has taken an active role in
encouraging beekeeping within the city limits.   The version of the
story I found a link to was in the Madison Commons.

Apparently beekeeping was prohibited in town (though the prohibition was
rarely enforced, except in the case of complaints).  The ordinance was
changed to allow urban beekeepers to keep hives.

There are specific regulations, such as 25′ distance to the nearest
neighbor as well as a  requirement to supply a fresh water source near
the bees (very important – especially in urban settings). 

Flight barriers – fences, shrubbery, or  sheds are also required.  This
is a simple bit of beekeeping etiquette if you have close neighbors.
Bees will fly straight in and out of the hive entrance, usually just a
foot or two off the ground.  They’ll maintain this altitude until 
forced to go up or down.  Constructing, planting, or placing the hives
in front of an existing barrier they must fly over ensures they will
maintain a higher altitude coming and going and not zip across your
neighbor’s lawn at kid-eyeball height. 

I’m currently learning stuff like this and much, much more in the
brand-new Virginia Master Beekeeper Program, taught by the most
excellent Bee Professor on the planet, Dr. Rick Fell. Honeybee
physiology and sociology is absolutely astounding.  I’ve been beekeeping
for four years now, and am just finding out with this class how much I
didn’t know.  I was also unaware that incidences of beehive thievery are
at an all-time high, hence the out-of-site suggestion.

I’ll probably continue to pop out with the occasional post on bees,
because I just can’t curb my enthusiasm.  "Cleansing flights" might be a
good topic…

   Slide from Dr. Richard Fell’s immense bastion of knowledge.