weather – The Garden Professors™

When trees can’t predict weird weather

Our normally mild corner of the country got hit early and hard with cold weather a few weeks ago. For several days straight, our home thermometer read anywhere from 22-25F. Now, Seattle routinely gets temperatures this low sometime during the winter. But this cold spell came very early – much earlier than our regionally adapted trees and shrubs were used to. The effect on our plants was significant.

Rhodies react to cold but tolerate the freezing temperatures

Trees and shrubs start getting ready for dormancy in the summer. They key in on the progressively shorter days and make biochemical preparations that are unnoticeable. When the first frosty evenings arrive, leaf color changes begin immediately. Chlorophyll, proteins and sugars are scavenged and stored in trunks and roots – we see leaves change from green to red, orange, yellow, and eventually brown. Slowly an abscission layer is laid down at the base of the leaf petiole, and when the layer is complete the leaf dies and falls.

But this year the trees weren’t ready. It got cold really fast, and green leaves died on the trees. And they are still there. Eventually these old leaves will fall, though some of them may stay on until spring.

Both the hydrangea in the foreground and the styrax in the back have retained their leaves after the cold snap.

What does this mean in terms of tree health? Well, it won’t kill them, but it does set them back in terms of food storage. A lot of the nutrients that were still in the leaves when they froze are lost to the tree. So there may not be as many reserves for winter root growth, or for spring leaf flush. Overall, we could expect to see less than normal growth in established trees and shrubs.

(Not so) pretty in Pink

The weekend’s weather forecast portended some lousy conditions and, unfortunately, this time the forecasters got it right. The outlook map for the Lansing area put us squarely in the dreaded Pepto-Bismol pink ‘Icy mix’ swath from Oklahoma to Maine.

Last night and this morning was a non-stop cacophony of “Snap! Crash!” as icy limbs headed earthward. About 4:30 this morning my wife saw a bright flash burst across the street and almost immediately we heard all our of appliances stop. No power. After breakfast I negotiated a slalom course of downed tree limbs to a nearby supermarket which was operating on its emergency generator. Last minute Christmas shopping had instantly given way to stocking up on bottled water, camp-stove fuel, batteries, and Presto logs.

The short drive back and forth to a store made the immensity of the storm immediately apparent. Most people we know are without power and I suspect for most of us it will be several days if not longer before we get it back. Hats off to the men and women that are heading out to get things working again while the rest of us are staying inside and trying to keep warm.

I did get out and get a few photos around our place this morning to share, in case you’re in a location where you’re not experiencing the 2013 Ice Storm up close and personal. My alternative title for the post was “Beauty and the Beast.”

Our silver maple did what silver maples do in storm

Ice coating was over 1' thick in some cases — Ice coating was over 1′ thick in some cases

Lot of tree breakage everywhere. I'm surprised anyone has power today — Lot of tree breakage everywhere. I’m surprised anyone has power today

Does anyone really know how to handle weather ? – revisited

There are few things that bind us together like weather. No matter what a person’s socio-economic status, they get wet, hot, or cold just like the rest of us. Ok, if you’re rich enough you can afford to move where the weather suits your clothes, but if you’re like most of us, you have to deal with whatever Mother Nature sends your way. And, if you’re a typical American, few things give you more self-righteous satisfaction than knowing that out of the 300 million people in the country, YOU are the only one that knows how to cope with weather. So as this weekend’s winter storm brought wintry conditions to parts of the country that don’t often see snow, I could hear people chortling smugly from Buffalo to Fargo. Of course people in Dallas don’t know how to drive in snow; why the F#@$ would they? The chortlers also conveniently forget that that first full-on snow usually brings plenty of misery to northern climes as well.

It’s all basically a cycle. Someone, somewhere, sometime will be laughing at you and your neighbors. People from the Northwest snicker when schools in the Midwest delay their start because of fog, people in Michigan laugh when the South gets snow, and people in the South can’t understand the hysteria of a Midwestern heat wave. But thanks to Jimmy Kimmel, at least we can all laugh at southern California.

It was a dark and stormy night

A wild and wooly night for many of us last night. A powerful line of storms moved through the Midwest yesterday afternoon and evening, spawning numerous tornadoes, primarily in Illinois and Indiana. Here in Michigan we were spared the tornadoes but had to cope with a long night of high winds, gusting up to 70 mph along the Lake Michigan lakeshore.

The high winds and heavy rains lead to widespread tree damage and power outages. Dealing with a yard full of damaged trees can be an overwhelming and sickening feeling for homeowners. If you are a homeowner or someone who advises homeowners, there are several good resources on the web to assist with the process of assessing storm damage to trees after a storm.

The National Arbor Day Foundation has a storm recovery website that provides practical tips for dealing with storm damaged trees. The website also includes resources for media including press releases and images that are useful for educating the public on steps to take during storm recovery.

The Minnesota Department of Natural Resources also has useful storm recovery information on their website.

For those dealing with storm damaged trees keep these points in mind:

-Stay at least 25 feet away from any downed power lines and contact local authorities to report downed lines.

-Damaged trees and hanging tree limbs are extremely dangerous. Trees that are damaged in storms often have decay or other hidden defect and can drop without warning. Walk around – not under – damaged trees and limbs. Keep children away from damaged trees.

-If you are unsure if you can safely remove a limb or damaged tree, always err on the side of caution and contact a professional arborist or tree service company.

-Be wary of ‘door-knockers’, individuals that descend on storm-ravaged areas that offer to perform tree clean-up or removal. Reputable, professional tree service companies rarely, if ever, solicit business door to door. Working around damaged trees is dangerous work that requires professional training and equipment. Look for arborists that are insured and certified by the International Society of Arboriculture.

The wackiness continues

It seems like every year we end up talking about ‘weird’ weather; either it’s extreme heat, extreme cold, too much rain, not enough rain, and on and on. Here in the upper Midwest and other parts of the central US, however, 2012 is clearly a year to remember. Our winter was fairly unremarkable until we hit 8 days over 75 deg. in mid-March. This pushed our growing degree days up at least 3 weeks and set the stage for widespread late-freeze damage in April, wiping out the state’s cherry, peach, and plum crops. Summer turned out warm and dry, highlighted by record-setting heat in July.

Weekly average high temperatures from MSU Hort Farm weather station: 2012 versus average of 15 previous years.

Now that we’ve seen some relief from summer’s drought and heat, we’re experiencing one more weather-related phenomenon: stress flowering. At my place I had lilacs and azaleas start to flower in August. We have also had reports of crabapples flowering in the eastern part of the state. Trolling around the web, I ran across a photo of magnolias blooming this month in Kansas City.

Magnolia flowering in mid-September. Source: Kansas City Star

So, what’s going on? Severe heat and drought can cause plants to go into a state of eco-dormancy. Typically we define “true” dormancy as a state where plants won’t grow, even when environmental conditions are favorable. Eco-dormancy represent the flip-side; plants should be growing but can’t due to severe environmental stress. In some cases the stress can induce flowering, such as we’ve seen this year. We have also seen examples of trees that have re-flushed, sending our new leaves after shedding leaves during the peak of the drought.

Will any of this cause long-term problems for trees and shrubs? Probably not. Stress flowing tends to be sporadic so most flower buds on a tree or shrub are likely to be unaffected. Shoots that re-flush late in the summer may or may not be able to harden off before winter. If not, they will be subject to freeze injury just like shoots that flushed earlier the spring. The main concern for 2012 is the cumulative toll of our environmental extremes.

What to do when it’s still raining?

It’s almost May…and it’s still raining. Even for our normally wet spring climate, this has been an unusually soggy year. I’m also blaming the weather on my 3rd or 4th cold so far this year, which has knocked me flat for the last 6 days (which was why I had no Friday puzzle posted). So in between blowing my nose, hacking my lungs out, and generally feeling sorry for myself, I started looking over 10 years’ worth of photos of our home landscape.

You’ve seen bits and pieces of this before in some of my postings. But one of the spots I’m most proud of is the tiny east-facing side yard that originally contained lawn, a lilac, and a border of arborvitae. Within the first few years the lawn came out and plants started going in. In 2004 I’d installed some small rhododendron, a redbud (left foreground), and a whole lot of woodchips:

Since then we removed the lilac (it had been planted too close to the garage and was a powdery mildew magnet), put in an arbor and wisteria (on the right), and added a few more plants (ferns, bleeding hearts, various bulbs and tubers, etc.). Here it is two (2006) and five (2009) years later:

This year we’ll finish off the area with some flagstone pavers.

One of the main reasons I’m so pleased with this area is that it was inexpensive to redo and it established quickly. We bought the redbud, the wisteria, and the bulbs, but the rest were donations from friends’ gardens, or volunteers that popped up elsewhere in the yard, or plants that someone else wanted removed (like the larger rhody in the far left corner and the dogwood in the right foreground, 2006 photo). The chips were free; the flagstones were a major score from craigslist (free to whomever would pry them up and lug them out). All the purchased trees and shrubs were barerooted; and root-pruned if needed before planting. Upkeep is minimal except for a bit of pruning and spot watering during the hottest summer months; we’ve lost no plants other than the occasional bulb poaching by squirrels.

It’s just a little bitty sideyard…but I enjoy walking through it every time I’m outside, even in the rain.

Confessions of a Weather Channel Addict

My name is Bert and I’m a Weather Channel junkie. It started innocently enough; sneaking an occasional peek at the local radar. Then I found myself sticking around for the next Local on the 8’s just for the smooth jazz. The progression from there was steady and predictable: Glued, trance-like, to the couch for re-runs of ‘Storm Stories’ and ‘When Weather Changed History’; setting my alarm 20 minutes early to catch ‘Wake up with Al’ so I could get my morning Stephanie Abrams fix. My downward spiral was further enabled by weather.com. I knew I needed help when I found myself checking the local radar to see if it was raining instead of just looking out the window.
Admit it. If you’re a gardener or work with gardeners, you’re probably hooked too. Hard to imagine a Saturday or Sunday morning that doesn’t start with tuning in to TWC or clicking on weather.com. The local radar and weather warnings, of course, are indispensible. We had a frost advisory in our area last night and I’m sure some folks will get an extra couple weeks out of their annuals if they paid attention and got them covered.

An often-overlooked feature on weather.com that I encourage gardeners and landscapers to use is the wind forecast. If you go to your local hourly forecast and click on ‘details’, it provides an hour-by-hour forecast for local wind conditions. This is a great way to plan any herbicide applications (e.g, Round-up or Weed-B-gone) you may be contemplating. Doing a little planning and spraying when conditions are calm is one of the best ways to avoid off-target injury.

So clearly there are plenty of reasons to keep us hooked and tuning in, even if some aspects of TWC are getting just a little too predictable:

Studio anchor: And now we go to Jim Cantore, who’s on the Outer Banks where Hurricane Holly is about to make landfall. Jim, what’s the latest out there?

Cantore (braced against a gale but looking studly in his official Weather Channel raingear): Well, just like the other 73 hurricanes I’ve been in, it’s raining. And the wind is blowing really, really hard!

Cut back to studio anchor: Thank you, Jim, for that insightful report.

The Weather Channel, live by it.

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Riding the storm out

This past weekend marked our first real bout with severe thunderstorms here in Mid-Michigan. Several lines of storms moved through the mid and southern part of the state and northern Ohio. The storms in southern Michigan and Ohio also spawned some tornadoes. Around here, storm damage was confined mainly to downed trees causing power outrages and some damage to homes and buildings.

Severe weather outbreaks provide some opportunities to observe tree failures and gain insights into how they can be prevented. Or, as Yogi Berra put it, “You can observe a lot just by watching”. I was at a little disadvantage in scouting out tree damage from out most recent storm because we were traveling over the weekend and I wasn’t able to get out and about to survey damage until Monday evening. As it turns out the area most heavily affected by the storm is also fairly affluent. Folks in these neighborhoods don’t tolerate downed trees lying around very long. Nevertheless, I did make a couple of interesting finds.

A common sight after a storm in this area is wind-throw in shallow-rooted species, such as spruce and pines. We didn’t see a lot after the current storm, which was probably due to the fact that the storm moved through quickly – most of the high winds lasted only a few minutes – and the storm was not preceded by prolonged heavy rains.

I don’t have any specific data but I have seen several cases where wind-throw was occurred on trees in which mulch was underlain with landscape fabric. Perhaps coincidence, but another strike against the stuff in my mind.

This maple provided one of the best (or worst) examples I have seen of planting too deep. The tree snapped off about 6” below ground line.

Note that there are plenty of pretty stout roots that look like structural roots near the surface, but none of these originated near the current ground line. The tree was on private property and time constraints prevented me from getting permission to do an excavation, nevertheless, it would be interesting to try to find the original root flare.

By far the most common problem in this storm, and most of our typical thunderstorms, was large limb breakage associated with narrow crotches. This occurred in a variety of species; oaks, maples, elms, pines. Narrow branch angles often form from multiple leaders, which results in weak branch attachment as included bark forms and gradually reduce the proportion of wood attaching the branch to the tree. The encouraging thing, or maybe discouraging depending on your point of view, is that this is one of the most easily preventable tree defects. Pruning double leaders or multiple leaders back to single leaders and eliminating other poor branch angles when small can easily prevent this type of breakage. For most of our garden-variety thunderstorms, eliminating narrow crotches would probably eliminate 50% or more of our tree-related storm damage.

Last-Frost-Date Roulette

We all play the game – at least the more impetuous among us do. You sneak a few tender things out into the garden, or on to the patio. When the temperature drops and there’s a frost warning, no problem…just cover them up or bring them in.

Unless you forget.

This WAS a rare and neato Pereskia aculeata ‘Variegata’. Paul W., please send me another…

Before dawn on Monday morning, (May 9) the temperature on our little mountainside dropped below freezing for four hours, going as low as 29.5 F according to our weather station. I had tucked everything back into the greenhouse or up under the eaves…except for the contents of a built-in planter on a far outpost of our deck.

Top o' the frosty mornin' to ya...
Dahlia Mystic Desire, edged in frost at 7:00 a.m., May 10.

NOAA has a handy set of maps that illustrate last dates of “Spring freeze occurrence”. The maps present data averaged between 1951 and 1980.

Walking around the garden last evening with a nice hot cup of martini, I surveyed the damage. Big, juicy-stemmed bleeding hearts that seem so fragile and succulent? Not a speck of injury – but they’ve been up since March. Newly emerged (and really expensive) Asian Jack-in-the-pulpits looked like wet rats. Annuals and tropicals exposed out in the open didn’t stand a chance. Early-to-leaf-out trees can take a beating, too. Japanese maples are notoriously precocious, flinging their fabulous foliage out as much as 45 days prior to last frost here. They’re in pretty good shape now, having acclimated a bit. But for our previous hard frost,15 days ago, we had eight little maples individually draped in white row cover (looked like Halloween).

No longer desirable...
Dahlia Mystic Desire, kaput at 7:00 p.m., May 10.

So why the damage on some and not others? Plants differ in the amount of sugars, proteins, and other compounds that affect the osmotic potential in cells. The lower the content of these compounds, the more likely freeze damage will occur. Young and unacclimated tissue tends to have a higher ratio of water. Like an overfilled water bottle stuck in the freezer, something’s got give as the liquid crystallizes and expands (vast oversimplification, sorry). Cells burst, or are crushed from the freezing of intracellular water, and fluid goes everywhere – hence the limp, dark, water-soaked appearance.

Fog or dew on the plant can delay injury; as external moisture freezes, in gives off heat (an exothermic reaction; one of the amendments to the Laws of Thermodynamics), until all the water is frozen. This is why citrus groves are continually sprayed with water during a freeze event. So it also depends on the duration of the cold; if temperatures just briefly drops below freezing, damage is minimal. Four hours for non-acclimated tissue? See the grim photos for results. Will I wait until May 15 to plant stuff out next year? Absolutely, positively, not. We’re due a no-late-frost spring!