Mitchella repens … Partridge Berry … an Evergreen Native Groundcover for Shade

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Partridge Berry in its Natural Setting

One of the questions that came up regularly when I was working the hotline at the local county Extension office, is a recommendation for an evergreen ground cover for shady spots.  I had the same issue when I created my own shade garden … something that would have year round interest, but complement my desire to emphasize native species, although that was only one consideration.

The solution was literally right next to me, as a walk in my woods revealed with the lovely plant Partridge Berry, or Mitchella repens.

Not only is Partridge Berry (Mitchella repens ) beautiful, evergreen, shade-loving, and native to Eastern North America, but there’s also a fascinating aspect about its flowers and fruit, from a botanical, and evolutionary point of view.

According to the U.S. Forest Service Celebrating Wildflowers website, the “… genus name Mitchella was given to this plant by Linnaeus for his friend John Mitchell, a physician who developed a method of treating yellow fever. The species name repens refers to its trailing or creeping habit.”

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Here’s the part I found fascinating: The plant is dimorphous, meaning “occurring in two forms”:

In late spring, two beautiful white flowers (with one calyx) each open their four petals to entice insects to collect their nectar. Each blossom has one pistil and four stamens. The pistil in one is short and the stamens are long. In the other it is just the opposite. … Because of this no flower can fertilize itself–all flowers must be cross-pollinated by insects, and both flowers must be pollinated to get a single healthy berry. A berry will stay on the vine until after the blooms appear in the spring unless a hungry bird finds it nestled among the fallen winter leaves.

How cool is that?  The twin flowers produce, together, only one berry.

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Here’s a closeup, where you can see residual evidence of the fusion.  The berry is edible, and persists through the winter, assuming it is not consumed by “ruffed grouse, northern bobwhite, sharp-tailed grouse, and prairie chicken.

The fruit is also “frequently eaten by raccoons and red fox” and it has been reported that “partridgeberry made up 2.9 to 3.4 percent (dry weight) of the summer and fall diets of white-tailed deer.”

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Here’s a picture of the two flowers in bloom.

It’s easiest to spot the plant in its natural setting while hiking in late Fall, or early Winter before snowfall, or early Spring after snowmelt.

Back to the Forest Service article:

Some gardeners consider Partridge Berry a must for winter gardens. During the cold days of late winter Partridge Berry is a treat to the eyes with its deep, dark-green leaves and occasional scarlet berries. In a garden setting this evergreen prefers shade, accepting the morning sun. Partridge Berry is extremely difficult to propagate from seed.

The best way to introduce this native into your garden is through 1 year old cuttings or by division. In the garden situation they will form a thick, substantial ground cover. Once established they are relatively trouble free with the only required maintenance of keeping garden debris from covering the mats.

As always, do not wild collect plants from public lands and only from private lands when the landowner grants permission. Partridge Berry is a commonly available plant from native plant nurseries especially those who specialize in woodland plants.

I love the symmetrical variegation in the evergreen leaves, a bright, light yellow line bisecting each leaf, and the delicate, less visible veins.

It’s a great alternative to Vinca, an introduced species from Europe that appears on invasive species lists in our area.

A Google search will reveal many potential on-line sources for buying Partridge Berry plants, or check with a local nursery, or independent gardening center in the native plant section.

A tale of two winters

I’m not sure we’ve ever been quite so ready for the calendar to turn to March. That’s assuming, of course, you live somewhere east of the Rockies. For people on the west coast, the sentiment is probably, “When are those people back East ever going to quit b-tching about their weather…” While I was dealing with 10” of snow and 25 mph winds whipping up 3’ deep drifts on Super Bowl Sunday, my friends back home in Washington state were mowing their grass. At this point I don’t even remember what my lawn looks like.

I have to confess that I thought winter 2014 was an anomaly and that we wouldn’t see weather that cold again any time soon, if ever. Boy, did I get wrong number. While winter 2015 is not exactly a carbon copy of 2014, I’m not sure most of us can tell the difference. In case dealing with sub-zero wind-chills for weeks on end wasn’t torture enough, I dug into the weather records from our automated Michigan EnviroWeather network to see how the past couple of months stacked up. To keep things simple I queried the records for the past twenty Januaries and Februaries. I just include those months since we don’t have any data for this March yet and those are the months we typically get our coldest weather, though we occasionally also get sub-zero in late December.

Over the last 20 years the past two winters have been by far the coldest, and it’s not even close. Over the previous 18 years the average daily low temperature for January and February was 17.0 deg. F. In 2014 the average low was 5.9 deg. F; this year it was 5.8 deg. F.

Daily low temperatures in Jan. and Feb. of 2014 and 2015 were more than 11 degrees below the average of the previous 18 years.
Daily low temperatures in Jan. and Feb. of 2014 and 2015 were more than 11 degrees below the average of the previous 18 years.

Not only was it colder on average but we’ve had more extreme cold events in the past two years as well. Between 1996 and 2013 we averaged less than one day per year with low temperatures below -10 deg. We were below -10 deg. F on eight days this winter and nine days last winter. The bottom end of our USDA Hardiness Zone 5 is -15 deg. F. We have been below that mark five times this winter, compared to twice last year and zero times in the previous 18 years.

Over the past 20 years we rarely dipped below -10 F. We've been colder than -10 seventeen times in the past two winters.
Over the past 20 years we rarely dipped below -10 F. We’ve been colder than -10 seventeen times in the past two winters.

Obviously this data is specific to mid-Michigan, but I suspect most locations in the Midwest and Northeast will have similar stories to tell. So what does all this mean? For one, our hardiness zones are what they are for a reason. Folks that like to ‘push their zones’ (you know who you are), have gotten away with it with impunity for nearly 20 years. This winter and last were time to pay the piper.

The owner of this Cedrus deodora 'Polar winter' (zone 6) had gotten away with pushing their zone for 10 years before things came to grinding halt in 2014.
The owner of this Cedrus deodora ‘Polar winter’ (zone 6) had gotten away with pushing their zone for 10 years before things came to grinding halt in 2014.

The other take home lesson is that climate doesn’t consistently move in one direction. Even if we’re in a period of general warming, extreme events will still occur. This is important to remember as we think about planning for projected future climates. We have seen the appearance of several climate-change friendly plants lists. In some cases the authors have simply looked at projected climate zones and moved plant selections northward. The problem with this approach is tree survival is based on extremes, not on averages.

You CAN grow it, but is it worth it?

As winter sets in here in Michigan, I’m seeing gardeners deploying winter protection. Like this, which I saw on a visit to Hidden Lake Gardens with some friends recently:

pinus contorta Chief joseph covered

Well. Isn’t that attractive? Come around to the far side, and you see this:

pinus contorta Chief joseph

Pinus contorta ‘Chief Joseph’ which is a stunningly beautiful conifer, green in the summer, this brilliant shade of gold in the winter. Sadly, those gold needles are also incredibly prone to turning a less brilliant shade of brown if exposed to too much winter sun and wind. Hence the ever-so-attractive sun-and-wind shade they’ve installed here.

Call me old-fashioned, but the point of a garden is to be pretty, and though you CAN wrap delicate shrubs in burlap or upend styrofoam cones over tender roses or even (yes, I’ve seen it) put little roofs over your hardy succulents to keep excess rain off of them, but is it really worth it? For me, if I have to put something ugly on my plants to keep them healthy, it isn’t worth it. In my garden, I’d lean towards something else I also saw on that visit:

Chamaecyparis obtusa Crippsii

Chamaecyparis obtusa ‘Crippsii’ No, it isn’t quite as stunning as the pine… but it will grow and not turn brown, with no fuss.

What about you? Are there plants you are willing to make your garden ugly to keep happy?

 

Don’t need a weatherman to know which way the wind blows

Posted by Bert Cregg
Yesterday afternoon I did a little fall garage clean-up and listened to former MSU Extension colleague Dean Krauskopf’s call-in gardening show on the radio. A couple callers in a man phoned the show worried about his Japanese maple tree, which had a near-death experience from this past winter’s severe cold. The man had heard this coming winter was supposed to be just as bad as last winter and he wanted to know how best to protect his struggling tree from further calamity. Dean quizzed the caller for details about the tree and the site and gave some reasonable advice to try to modify the micro-environment around the tree to limit exposure to winter wind and cold. But I wondered where the caller got his information that winter 2015 was going to be as bad as 2014. As if anyone around here needs a reminder; January-March 2014in Michigan was the coldest since 1978 and the 4th coldest on record, with most locations reporting snowfall totals well above average. Many surrounding states has similar winter weather issues.

To get some insights on predictions for the upcoming winter, I consulted with the two most trusted sources of such information: The NOAA Climate Prediction Center and the Old Farmer’s Almanac.

The Climate Prediction Center maps present probabilities of colder or warmer than average weather for a given three month period. The most recent NOAA projections available on-line are predicting near-normal temperatures for January-March 2015 for most of the eastern half of the country, above average temps for the Northwest and below average for Texas and Florida. NOAA predicts below average precipitation for the lower Great Lakes and Northwest and above average precip for much of the South.

Current NOAA temperature predictions for Jan-March 2015
Current NOAA temperature predictions for Jan-March 2015
Current NOAA precipitation prediction for Jan-March 2015
Current NOAA precipitation prediction for Jan-March 2015

Apparently, however, Dean’s caller is dismissing NOAA and all of their satellites and computer models and is relying on the Old Farmer’s Almanac instead for his long-term weather outlook. The Old Farmer’s Almanac is currently predicting colder and drier than normal for most of this upcoming winter for the lower Great Lakes.

Current temperature outlook for lower Great Lakes regions from Old Farmer's Almanac.
Current temperature outlook for lower Great Lakes regions from Old Farmer’s Almanac.

So, how much stock should we place in these predictions? Let’s step inside the Wayback Machine for a moment and see what each source was saying a year ago about the then-upcoming winter of 2014. NOAA and the computers are up first.

For most of the eastern U.S., NOAA predicted a warmer than average Jan-March 2014 with normal precip. Ooh, sorry about that NOAA but we thank you for playing ‘Guess that Winter’! Please be sure to pick up your parting gifts on your way to our Loser’s Lounge.

September 2013 map of NOAA prediction for Jan-March 2014 temperatures.
September 2013 map of NOAA prediction for Jan-March 2014 temperatures.
September 2013 map of NOAA predictions of Jan-March 2014 precipitation.
September 2013 map of NOAA predictions of Jan-March 2014 precipitation.

Next up is the Old Farmer’s Almanac, which predicts winter weather based on… well, no one’s quite sure. In any event, this time last year the Almanac predicted Jan-March 2014 would be mostly warmer and drier than normal for the lower Great Lakes. Oh no, bummer Almanac. Looks like you and NOAA can commiserate in our Loser’s Lounge. And that means Old Man Winter repeats once again as our champion!

Old Farmers Almanac September 2013 weather prediction for Nov. 2013-Oct. 2014.
Old Farmers Almanac September 2013 weather prediction for Nov. 2013-Oct. 2014.

So, what does all this mean for Winter 2015? Even with huge datasets and sophisticated models, long term weather projections are an iffy proposition. And, as much as everyone loves to say, “See, the Old Farmer’s Almanac was the only one to get it right”, there is little evidence that it does better than chance alone. Beyond that all we can say with certainty is that NOAA and the Computers would make a really cool name for a rock band.

You and me Baby ain’t nuthin’ but mammals…

As spring slowly makes it appearance in the Midwest, homeowners and landscapers are likely to continue discovering damage from our record-breaking winter. While brutally cold temperatures and heavy snow loads took their toll in many areas, some of the most severe damage that occurred to landscape trees and shrubs this winter was caused by mammals.

Our long, harsh winter resulted in heavy feeding damage by deer, rabbits and voles, also called field mice. Depending on the age and type of plant and which animal was feeding on it, mammal damage can range from light pruning to death of a tree or shrub. Developing a strategy to deal with animal damage requires proper identification of the offender. Here are clues to identifying mammal damage.

Vole damage
Voles or field mice are small rodents that gnaw on tree and shrub stems. Voles do not hibernate and are active throughout the winter under snow, so feeding damage that occurred near ground-line when the ground was covered with snow is likely vole damage. Although they are small, voles can wreak a lot of havoc. They can easily kill small trees or branches on larger trees by girdling stems, or removing the bark around the entire circumference.

Vole damage on concolor fir
Vole damage on concolor fir
Voles (or field mice) can completely girdle trees.
Voles (or field mice) can completely girdle trees.

Deer damage
During the winter, deer feed on the ends of many types of trees and shrubs. Evergreens, especially arborvitae, are among their favorites. In most landscapes in this area, a “browse line” is a common feature on arborvitae. Eastern white pine, maples, birch, dogwoods and viburnums are also favored trees deer browse. This winter, I received reports of deer browsing on secondary species, such as Austrian pine, reflecting the severity of the winter.

A deer browse line on arborvitae.
A deer browse line on arborvitae.

Rabbit damage
Rabbits can cause damage that may resemble feeding by either voles or deer. Like deer, rabbits will chew the ends off of deciduous trees and shrubs. A close inspection of the end point will often indicate the culprit: rabbits typically leave a clean, angled bite mark, whereas deer tear or break stems, leaving a rough edge. Like voles, rabbits can also girdle stems of trees and shrubs. In winters with heavy snow cover like this one, the height of the damage can provide a clue; vole damage will extend down to the soil surface, while rabbits work above the snow-line.

Clean, angled bite-marks: A telltale sigh of rabbit activity.
Clean, angled bite-marks: A telltale sigh of rabbit activity.

Managing mammal damage
Managing mammal damage is often difficult and multiple strategies may be needed. Excluding deer with fencing can be highly effective, but is not practical in many instances. Deer repellents can also be effective, but may wear off over time or become less effective as deer become hungrier as winter wears on. Around our place, our dogs to a good job of keeping deer and rabbits at bay, but of course require their own care and feeding.
Reducing weeds and ground cover can help to reduce damage by rodents by eliminating cover from their predators. Trapping may be effective for controlling rabbits, but is usually not practical for voles. Baiting can be used for voles, though care must be taken to avoid poisoning non-target animals. In some situations, erecting raptor perches can also be helpful in keeping rodent populations down.

Feel the burn…

Winter burn on Douglas-fir
Winter burn on Douglas-fir

One of the most obvious impacts of this winter’s winter is rapidly becoming apparent in Michigan and other parts of the Midwest: winter burn on conifers. The primary symptom of winter burn is needle browning, especially on evergreen conifers in exposed locations. Needles may be damaged by extreme cold or the browning may be associated with winter desiccation as needles lose moisture during brief warm-ups. Winter burn is one of those situations that draws a lot of attention because it can look devastating; yet it often has relatively little long-term impact on plants.

Winter burn on dwarf Alberta spruce in Michigan
Winter burn on dwarf Alberta spruce in Michigan

The key to the lasting effects of winter damage on evergreens is the extent to which buds are damaged.
With a little practice it is relatively easy to determine the state of conifers buds. With your thumb and forefinger pull the bud scales from the top of the bud. With a good hand lens or dissecting scope you will be able to see the bud primordia. On healthy buds this will be bright green; on damaged buds the primordia with be brown or black.

Buds from conifers with severe needle browning may be alive (top) or dead (bottom).
Buds from conifers with severe needle browning may be alive (top) or dead (bottom).

I recently examined buds from Douglas-fir trees on campus that had severe needle browning this winter. In several cases, trees had severe needle browning but the buds were fine. These trees will likely put on a normal growth flush this spring and in a year or two it may be difficult to tell they were ever damaged – assuming we don’t have a repeat of this winter’s severe weather.

A 'snow-line' indicates the depth of snow when needle injury occured
A ‘snow-line’ indicates the depth of snow when needle injury occured

On some other trees, however, the buds had been killed by this winter extreme cold. This doesn’t mean these trees are dead – they may still form adventitious buds along the stems – but it will certainly set them back and will likely impact their form and symmetry.

How cold WAS it?

The line ‘How cold WAS it?’ has been a lead-in for stand-up comics for years; as in, “It was so cold politicians had their hands in their own pockets…” or “It was so cold the mice were playing ice hockey in the toilet bowl…” Like everyone, I’ve heard lots of discussion these days about just how cold this winter has been. We certainly know that this winter bucks a recent trend of relatively warm winters in the Midwest over the past two decades.
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However a popular notion around these parts, especially among old-timers, is that “this is the way winters used to be…” I’m a relative newcomer to Michigan, currently experiencing my 15th winter here. This is, by far, the coldest winter since I’ve lived here. But could this simply reflect my lack of perspective as a newbie? To gain a little insight, I pulled the long-term weather data for Lansing, which dates back to the 1880’s. I compared the daily minimum temperatures from this winter with the long-term average low temperatures and daily record lows.

low temps 2013-14

The results will come as no surprise to anyone who lives east of the Rockies. It’s been cold. How cold WAS it? Certainly well below average, especially since the Holidays. As of yesterday, 41 of the last 52 daily lows have been below average and we have been below 0 deg. F 19 times. Despite the prolonged cold, we have not broken any daily records although locations near here have.

So, are the old timers right? Are we just getting a glimpse of the way things used to be back in the day? The data suggest they are probably experiencing a bit of selective memory. If you’ve lived here long enough you’ve seen a few winters this cold and even colder. But this January will go down as one of the 10 coldest (at least) on record, so the idea that winter’s weather is like the ‘old normal’ is a bit of a stretch.