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Archive for the ‘Trees and shrubs’ Category

Now that gardening season is so close we can taste it, I’ve returned to the digital screen in a series of how-to videos, produced by the Boulder Camera, a newspaper that carries my gardening column. 

The first in this year’s series is a blatant attempt by me to distract all of you green thumbs from rushing forth into the garden and, in your enthusiasm for spring, do harm.  This happens in several ways, such as tilling soil, wet from snows, which creates clumps that dry into cement-like hardness. 

Other gardeners are starting seeds, which is fine.  Except some people are starting plants like cucumbers or summer squash, which, as a warm season vegetable, don’t get planted out until mid-May.  Giving a plant like that a 10 week head start is alarming – imagine how big they are on the 1st of August, which is ten weeks from when we direct sow them into the ground!  My zucchini is easily three-feet wide by that time.

Yes, the madness must stop, at least temporarily. 

Instead, dance between the rain showers this weekend and prune your fruit trees.  Check out how to work with cherry and peach trees in this week’s video.

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When the call came in that a spruce tree was ailing in a way that baffled the local nursery, I was intrigued.  Garden center staff see a lot of strange plant things, and in order to stump them, the problem is usually a puzzler.

Any time a tree behaves badly I rush out to see it, like an ambulance chaser following a crew armed with chainsaws and chippers.  To avoid the disappointment of arriving to find the tree is normal, I’ve learned to ask for a description of the problem over the phone first.

“It defies description,” said the kind man on the other end of the line, “I honestly don’t know where to begin.”  Now, normally people have no trouble putting their plant’s distress into words, usually relying on such phrases as “bugs are eating my tree,” “weird oozing,” or the popular “I just woke up this morning and it was dead.” 

Here was a man who was speechless to describe it, and because he was referred to me by the nurseryman, I drove over.

 That nurseryman was right; one had to see this to believe it.  Under a mature spruce tree, thousands of small twigs littered the ground, falling from a tree towering more than 30-feet tall.  They were short tips of the branches, still green and succulent with life, covering the ground and lower branches.

The rain of twigs had been happening since mid-December, and to keep up with it, the couple had been sweeping up the twigs, collecting bushels full to take to the tree mulching yard.

I did the reconnaissance a tree diagnostician should do when coming upon a new patient – stood back and looked at the tree.  There were no obvious signs of stress – it looked healthy, top to bottom.  Stepping closer, the twigs scattered across the ground showed no signs of insects or disease.  But there was one, odd thing: A pattern to the cut ends.  They were all clipped at an angle. 

I’d seen this before, just not on such a large scale.  That angle was familiar, and slowly my eyes lifted to the fence line, upon which two squirrels were sitting and giving me the stink eye.  “You’ve got squirrels,” I said, “nipping your branches.”

Squirrels will do this, in winter or spring when food is hard to find.  They also do it at random times of the summer too, for no apparent reason.  Some foresters have suggested boredom.  And because the squirrels aren’t stripping the bark or eating the wood, I believe them.

There’s nothing to be done to stop the problem, but the good news it that the tree will be fine.  Although the damage seems alarming, a healthy tree can take a bit of twig loss.  If you find your tree suddenly losing its tips, check the discards closely for the tell-tale angled cut; if you find it, you’ll know it’s those squirrels, and not a disease.

This post was previously published in the Longmont Ledger.

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Some states elect wrestlers, others movie stars.  But in Colorado, we’ve elected a brewer.  Ok, yes, before that he was a geologist, but for any gardener who’s toiled under the blazing sun cutting a soon-to-be garden bed, well, a skill in brewing up cold, frosty beverages is more useful than being able to say that those rocks are limestone, granite, or gneiss.  Leave that conversation for after you’ve relaxed in the shade.

As John Hickenlooper is sworn in as the 42nd Governor of the state, I hope the man who launched the Million Tree Initiative in Denver takes that philosophy across the state.  Think of it – if an area the size of greater Denver can hold a million new trees by 2025, can’t he pack a few more into the state, until we become so thickly forested that we resemble Connecticut instead of Colorado?

Sadly, the answer is no, as anyone traveling the eastern or western borders of our state can attest.  It turns out we can’t really plant wall-to-wall trees, despite what bona fide treehuggers like myself want.   We’re limited by water, something trees need to grow big and strong.  On those borders I haven’t seen anything much larger than a shrub living outside of the towns. 

But a gardener can dream about taking over the planet with big, hulking vegetation, and trees are a gateway plant to other garden treasures.  Their shade keeps us cool, their branches support our children’s swings; the only thing I have against them is that they harbor squirrels who pilfer from my garden (it could be worse – if it gets much colder in portions of Florida, they’ll have those iguanas dropping from the trees again).

True, the Governor will have his hands full with the state budget, and yes, creating jobs, shrinking government and promoting the state are all worthy of his immediate attention.  But as long as he’s appointing a cabinet, toss in a tree czar – he can appoint an Ent to the position. 

Then the tree czar can get to work encouraging people to plant this spring, which is right around the corner.  There’s plenty to do, what with the new Front Range Tree Recommendation List being unveiled at ProGreen in February, The Colorado Garden and Home Show (also February), and planting starting in March.  

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Weather experts are predicting a mild winter this year, with above average temperatures and less snowfall.  Though “warmer” doesn’t mean it’s time to plan a luau for Christmas, scant snowfall and sunny days put your trees at risk from sunburn and dehydration.

So as you string your holiday lights, unpack your soaker hoses and break out the tree wrap, it’s time to get your plants ready for winter sunshine.  The secret to keeping trees healthy throughout the year lies in giving them moisture during the dormant season, and protect them from sunscald.       

What: Sun hitting trunks of young, thin barked trees warms the bark and cells underneath, causing them to lose their cold protection. As nighttime temperatures plunge, these cells freeze and burst, resulting in sunscald, an area that will be prone to disease in summer.

How:  Protect them for the first two to three years they’re in your landscape by wrapping them with tree wrap. Wrap from the ground upward, overlapping each layer over the lower one by one-half-inch until you reach the lowest branch. Use tape to hold the wrap in place, making sure the tape doesn’t stick to the trunk.  Mark your calendar to remove the wrap around April 15. 

Dragging wet hoses and getting sprayed with water can put a damper on anyone’s holiday mood, but with a little planning, winter watering can be a snap.

When:  Water once per month through March if we don’t have much snow or rain.  The lingering fall is keeping soil soft, letting rain soak in, but once temperatures get colder and the ground freezes, giving the trees a drink means watching the weather. 

Measure the snowfall at your house with a ruler to figure your plants’ watering needs. Write each storm’s accumulation on your calendar and add it up every four weeks.  Anything less than 12 inches of snow, total, means it’s time to water. 

How:  Pick a day when temperatures are above 40 and there’s no snow on the ground.  On frozen ground, water should be applied slowly, so spiral a soaker hose under the tree or use soft spray nozzle if watering by hand.  Have a timer on the faucet automatically shut off soaker hoses or plan on setting timers in the house to remind you to turn off water.

Tip:  Always disconnect hoses from faucets immediately after watering to prevent frozen pipes.  Plan to water at a time when you will be home to monitor temperatures, and water during the warmest part of the day.

Where:  Water around the dripline of the tree – the area that falls under the outer tips of the branches.   Soak the ground two to three feet on either side of the dripline, to a depth of 12 inches.  If using a soil needle, insert it no more than eight inches deep.  The roots that take up water are in the top 12 inches of the soil.

This post was previously published in the Longmont Ledger.

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A buddy of mine, Alison O’Connor, is a graduate student at Colorado State University.  She’s working on her Phd. in horticulture, and as part of her research, she had to plant 27 trees today.  Playing in the mud is always preferable to pushing paper on a desk, so a bunch of us went over to give her a hand. 

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The trees needed to be planted as correctly as possible, and Alison offered us a refresher on proper planting techniques.  Planted too low or to high, and the tree suffers, unable to root out  to support the 100-year lifespan. 

If you’re popping a tree into the ground this fall, brush up your skills by following her step by step advice:

Measure the height of the root ball to determine depth of planting hole, which should be one to two- inches shorter than the root ball.

Dig saucer-shaped planting hole, three-times the root ball width.  Straight sides limit root expansion, so to get your tree off to a fast start, slope the sides of the hole.  We had straigh holes dug with an augur, then sloped the sides with a shovel.

 Remove tree from container, clip any girdling roots, score the rootball, then set tree in place.  The “knees” of the rootball – the top edge of the soil – must be about two inches above the planting hole. 

If your tree has a “dogleg” from grafting (a curve in the trunk just above the graft), turn the rootball so the inside curve faces north.  This helps that sensitive spot avoid sunscald.

Pack soil around lower third of rootball, to help stabilize it.  then backfill the rest of the hole, leaving soil loose.

Water the planting area.

Mulch the tree.

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Cast your mind back in the not-so-distant past, to early October last year.  The days were warm, the nights crisp, and frost nipped at gardens but the season was not yet at an end.  Lulled by temperatures swinging from 21F to 88F, gardeners delayed the chores of putting the landscape to bed for winter. 

Frozen backflow preventer - photo courtesy of ALCC.

Suddenly, the weather threw us a curve ball, plummeting temperatures to a chill 16 degrees on October 10.  Plants froze, and so did sprinkler systems.  Some were lucky, escaping harm to their pipes.  Others didn’t see the damage until spring, when they started up their systems to water yards.

 That’s when gushers erupted from backflow prevention valves (the brass valve on the outside of homes), cracked by water turning to ice in the sudden freeze.  Calls to sprinkler companies skyrocketed, and homeowners shelled out $300 to $400 for repairs.  Vows were made to never let this happen again.

But Mother Nature is having hot flashes, and our landscapes still need water.  The resulting seesaw between day and nighttime temperatures are a roulette game for irrigation damage.  But you can keep your system safe with a few tips from the Associated Landscape Contractors of Colorado .

– Wrap your backflow preventer for as long as you want to keep your system operational.  Water in the preventer can freeze during cold snaps, so if you haven’t winterized your system when temperatures are due to dip, swaddle the backflow device with building insulation or towels, three to four inches thick, wrapping pipes all the way to the ground.  Cover it all with plastic, then secure it with duct tape.

– Once you decide to put the landscape to bed, winterize the system by shutting off the water and draining the lines.  Most systems in Colorado are designs that require blowout, but a few have manual or auto drains to remove water.  Should you have one of these, consider blowing out the system anyway, since lines settle over time and low spots often develop that hold water.

– Have your system blown out with an air compressor. Even if you’re a do-it-yourselfer for most tasks, blowing out a sprinkler system should be left to the pros.  A quick internet search for instructions on how to do this resulted in so many warnings shouted in bold, uppercase letters that it should be taken seriously.  According to the Hunter Industries website, using an air compressor to blow out lines can result in flying debris, although they don’t say if it’s from sprinkler heads shooting up like rockets out of the lawn.  The caution not to stand over the heads while they’re under pressure is an important safety tip.

To ensure your system is undamaged during blow out, look for a company with professionals certified by ALCC.  These Landscape Industry Certified Technicians must complete over 2000 hours of practical experience and 10 hours of testing in order to meet the standards of best practices the certification requires.   

Make your appointment soon, since October is a busy month for companies that offer winterization service.  Expect the blow out to cost $50 to $100, but it can save you higher costs come spring.

This post was previously published in the Longmont Ledger.

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What ever you do, stay out of the burned zone, is the message experienced foresters, researchers, and firefighters have for residents returning to their homes after the Fourmile Canyon and Reservoir Road fires.  The blazes that left hundreds homeless leave another hazard in their wake:  falling trees.

 “Really hot fires burn the tree, its roots, and all,” says Greg Sundstrom, Assistant Staff Forester with the Colorado State Forest Service, “those trees are likely to fall anytime between now and ten years from now.”  This makes the burn zone an area that curious homeowners and curiosity seekers should avoid.

Left unstable without anchoring roots, charred trees begin falling immediately.  “When I was on the firefighting crews in California, they’d have us eat our lunch squatting on our feet.  This was so we could move quickly when we heard a tree coming over, to get out of its way,” he said, describing the thud-thud-thud of falling trees. 

But not all trees killed by fire die right away. “We’ve looked at survivorship of ponderosa pines following fire in the Black Hills,” says Dr. Skip Smith, Department Head of Forestry and Rangeland Stewardship at Colorado State University.  “Immediate kill from the fire, where the foliage is consumed, is obvious.  But what we saw is that trees will die for four or five years after a wildfire.  It may appear green but eventually dies.”

If the cambium – that area of living cells under the bark – and the phloem experienced a lot of heat, those damaged spots girdle the tree.  It may be alive right now, but next year or the year after, it dies, he says.

Assessing trees for survivorship can be tricky, cautions Smith, but here are a few things to look for.  Check the crown, looking for percentage of scorched foliage.  If more than half of the crown remains green the tree has a good chance for survival; less than half and the tree’s odds diminish.  Total consumption, where the crown has burned off, means the tree is killed. 

Look for deep charring around the base of the trunk.  Ground fires burning duff, leaf litter, or other fuels against the trunk can kill the tree at ground level.  Like a pencil standing on its point, these trees are hazardous and will fall.  But if sixty-percent or more of the base is unharmed, it might survive, says Smith.

The good news is that ponderosa pines become resistant to fire, developing a thick, corky bark as they grow.  This insulates the cambium from heat.  Other trees aren’t armored from the heat, such as Douglas fir or lodgepole pines; they often fall victim to the flames.  Unable to regenerate from roots, pines succumb completely.  But other trees, such as Aspen, are remarkably resilient and will rise from the ashes to shade the land.

“Aspen will sprout up after fire if the heat into the soil isn’t great,” said Dr. William Jacobi, Professor of Tree Pathology and Extension Specialist at Colorado State University.  “In fact, often they’re not even noticed until after wildfires remove other trees.”   Native bushes are supposed to burn, he says, and come back quickly.

The big question for these areas is whether invasive plants will crowd into areas where smaller vegetation has burned off.  “The problem, now that invasives have moved into the forest, is that the invasives often do better after fire.  Seeds and roots survive, and they grow back before the natives,” he said.

At this time of year, experts recommend people whose property burned should stabilize the soil before snow flies, remove hazard trees, and plan revegetation for spring.  Contact the Colorado State Forest Service for a list of tree contractors.

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