Just do it – Page 7 – The Garden Professors™

Inspecting nursery plants, part ll

Well, I’m recovering from this simply horrific chest cold or whatever it is and feeling brain function returning. The last time we were at our virtual nursery, we were looking for root flare and inspecting the trunk for damage from improper bagging. Since we’re already down on our hands and knees, let’s consider roots. In general, you really don’t want to SEE roots, except where they meet the trunk (the root flare). The presence of coyly crossed “knees” in this photo is a clear indicator of a plant that wasn’t potted up quickly enough:

Likewise, while the fused, circling woody root mass in this next photo might be aesthetically interesting, it sure doesn’t make a functional root system:

It’s pretty easy to avoid these types of plants, because you can see the root problems before purchasing. The hidden root problems, such as those I’ve shown in earlier posts, are tough to find until (or if) you take all the extraneous stuff off of the root ball.

Finally, there is a new production practice that really fries my potatoes. What really makes me angry is that these trees had absolutely LOVELY roots – a nice flare, woody roots spreading radially – and then they were butchered – and left unprotected:

I can think of no legitimate reason for this practice. I’ll be curious to hear my colleagues’ thoughts, as well as those from the blogosphere.

Compost Tea? How About Compost Pee!

My news tab in Firefox is the BBC “latest headlines” page. It’s a great place to get pretty darn unbiased news plus the U.K. equivalent of “News of the Weird”. SO, relative to our ongoing discussion of composting…here’s a story ripped directly from the BBC headlines. Follow the link for a video (interview, that is).

Disclaimerage: I nor any of the other Garden Professors endorse this activity, nor any claims as to its usefulness, scientific relevancy, harrumph harrumph, etc,. etc,. etc. We do, however, fully endorse garden-related humor!

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Pee To Help Make Your Garden Grow

Gardeners at a National Trust property in Cambridgeshire are urging people to relieve themselves outdoors to help gardens grow greener.

A three-metre long “pee bale” has been installed at Wimpole Hall.

Head gardener Philip Whaites is urging his male colleagues to pee on the straw bale to activate the composting process on the estate’s compost heap.

He said the “pee bale” is only in use out of visitor hours, since “we don’t want to scare the public”.

He said: “For eight weeks now, male members of our garden and estate teams have been using the outdoor straw bale when nature calls. The pee bale is excellent matter to add to our compost heap to stimulate the composting process; and with over 400 acres of gardens and parkland to utilise compost, we need all the help we can get.

“There are obvious logistical benefits to limiting it to male members of the team, but also male pee is preferable to women’s, as the male stuff is apparently less acidic.”

By the end of the year, it was calculated that the 10 men from the 70-strong garden and estates team will make more 1,000 individual trips to the pee bale, contributing towards the compost for the estate. The estate said it will have saved up to 30% of its daily water use by not having to flush the loo so many times.

Rosemary Hooper, Wimpole estate’s in-house master composter, said: “Most people can compost in some way in their own gardens. Peeing on a compost heap activates the composting process, helps to produce a ready supply of lovely organic matter to add back to the garden.

“Adding a little pee just helps get it all going; it’s totally safe and a bit of fun too.”

Story from BBC NEWS:
http://news.bbc.co.uk/go/pr/fr/-/2/hi/uk_news/england/cambridgeshire/8357134.stm

Published: 2009/11/13 00:40:21 GMT
© BBC MMIX

To Prune Or Not To Prune, That Is The Question…

Dabney rules!

“Dabney! No! Wait!” Just kidding. Dabney Blanton, our lovely and talented horticulturist, knows not to prune the Artemisia in the autumn.

I imagine most gardeners have experienced a frost or freeze by now [exceptions: our Southern Hemisphere readers (howdy to Jimbo)…or anyone in the deeeeep south].

The perennials here in Blacksburg have taken a couple of hits; time to start trimming things back. In the Hahn Horticulture Garden and in my own personal garden, we like to leave perennials and ornamental grasses up as long as possible – gives us something to look at besides mulch, plus the wee birdies enjoy it.

But some perennials just look yucky after a freeze.

Case in point: foliage of the popular perennial Artemisia ‘Powis Castle’ resembles graying Kleenexes, hanging on the tips of the branches. HOWEVER, do not cut this back in the fall. It, like many other shrubby perennials, is sensitive to early winter whacking, in my experience, Buddleia and Caryopteris also fall into this category. Apparently the severe pruning sends a message to the plant to break bud – new shoots can appear and then “zap!” Wait until new buds appear in the spring, and be careful not to cut back too hard. I’ve killed a few that way, thinking I was doing them a favor.

“Cut ‘em back, cut ‘em back, waaaaay back!”

The best resource ever on maintaining perennials is Tracy DiSabato-Aust’s The Well-tended Perennial Garden. I should get kickbacks, as much as I’ve promoted this book! Truly a wealth of info – when should you cut it back, will it rebloom if deadheaded, don’t do [whatever] or you’ll kill it – all broken out by genus. Outstanding!

What Makes Growers Change?

Over the last few weeks I’ve said a lot of complimentary things about the Minnesota Nursery Industry and how they’re careful to avoid situations where trees are planted too deeply. What I haven’t mentioned is that there is a reason for this. During the 1980s and early ’90s trees were usually planted deeply with lots of soil over the uppermost roots. It was just common practice. Unfortunately this practice led to roots growing across the trees stems and, when those roots cross the stem, the roots always win (as you saw in Linda’s quiz last week)! Many, many trees planted in that era have trunks which enter the ground looking like the picture below. You can clearly see the roots strangling the tree. This photo was actually taken last year on this campus!

This tree is one of the lucky ones. These girdling roots were removed, the layer of soil over the crown was removed, the crown of the tree was inspected, and it was determined that this tree could survive. Many others planted during the 80s and 90s are not so lucky — in fact, many are suffering or dead.

An outcry over the last dozen years or so, mostly from cities (St. Paul and Minneapolis), led to changes in harvest by the nursery industry, and by the landscapers who install the trees. Yesterday I received a plan for planting trees up and down a major highway here in St. Paul to review. The specs were very specific — and similar to the specs that we see now across the Twin Cities and most of Minnesota. Root flare must be at, or even above, the surface of the soil.

I don’t want anyone to get the wrong idea. There are still those who sell nursery stock with the root flare buried deep under soil in the ball, and there are landscapers who dig a hole twice as deep as the depth of the ball before planting, but it’s becoming less and less of an issue as, in general, we seemed to have learned from past mistakes.

Inspecting nursery plants, part 1

I’m frequently asked to give seminars on selecting healthy plants at the nursery, especially trees and shrubs which can run hundreds of dollars. (Nobody seems to want a seminar on how to pick out a flat of petunias.) I routinely visit nurseries with my camera so I can record examples of good and not-so-good choices. What better forum to share these than on our blog? I’m also curious whether the problems we see in the Pacific NW are found elsewhere in the country, or in the world for that matter. So today we’ll hunker down on our hands and knees and inspect root flares.

The root flare (or root crown) is the point where the trunk meets the roots and should be wider than the rest of the trunk. The photo below shows this clearly:

In balled and burlapped trees and shrubs, you might not be able to find the root flare as soil and/or burlap cover the root flare. The tree below is burlapped far above its root flare:

Over time, many trees and shrubs buried too deeply will develop trunk rot. You can inspect for rot by gently peeling back the burlap from the trunk and looking for damage. Don’t worry, this doesn’t hurt the root ball or the trunk:

The tree in the above example already has some red flags – the presence of weeds on the soil surface suggests that it’s been in this pot for a long time. (And no, you don’t want to buy this tree.)
The most dramatic example of the problems that can occur is this weeping larch, which has been completely girdled by the rot induced by the burlap and twine around the trunk:

Lesson: It’s cheaper to wash your now-dirty pants than it is to buy (and eventually replace) a poor quality plant.

Wonderful wood chips

I’m in love…with arborist wood chips. These are not your beauty barks or other packaged mulches, but the chipped branches and leaves fresh from the tree crews. It’s a great way to keep this resource out of the landfill – and don’t even get me started about using this great mulch material for a “biofuel!”

I’ve written about wood chip mulches a lot, but thought today I would post some photos to show you how well they work in suppressing weeds and promoting growth in restoration sites. We published a paper on this in 2005, though we’ve been using them in ornamental and restoration landscapes for about 10 years.

Here’s a recent project: a wetland buffer enhancement was being installed in an area that was covered in Scot’s broom (Cytisus scoparius) and blackberry (Rubus discolor):

We had a brush cutter mow it to the ground, then put a foot of wood chips down. Later, we planted poplar, ash, willow and alder on the site:

We had to keep records, both written and photographic, for the county who monitors wetland projects. So we took photos every year at the same points for comparative purposes. Here’s what part of the site looked like immediately after planting and then after 5 years:

That’s not to say that we haven’t had to battle resurgent blackberries. They migrate over from the wetland itself (which we can’t touch) and tip root. But the increasing shade and competition from the trees has weakened their ability to take over, and the Scot’s broom has been gone for years.

So that’s one reason I love wood chips. I’ll do a follow up some week showing how they can be used in the home landscape.

The joys of arborizing!

It’s Holly’s day…but she’s off playing in a tropical paradise. So because she seems to be of a sunnier disposition than I am, I’ll post happy thoughts today.

One of my favorite pruning techniques, especially for small urban landscapes, is arborizing. This is a way of creating small trees out of large shrubs – and often, a large shrub is as much as a small landscape can handle. Rhododendrons are common landscape plants here in Seattle, and the larger ones lend themselves beautifully to this practice:

As you’ll notice in this example, arborizing not only creates an aesthetically pleasing tree form, but also moves the crown away from vehicular and pedestrian traffic. This protects the plant from damage and enhances access.

This also works wonderfully in landscapes where you would like to have layers of shrubs, rather than one massive plant. Look at this Ceanothus:

Arborizing this shrub not only allows planting additional plants underneath, but also allows some light into the house (note the window in the background).

Fall is generally a good time to prune (after the crowns have gone dormant). It’s easier to see trunk and branch architecture in deciduous trees, and generally places less stress on the plant.

If you’ve arborized shrubs before, which species work well for you? Which ones not so well?

See? I can be a happy blogger!

Where the Buffalo Roam

Just kidding. We have no buffalo on the campus of Virginia Tech, just lots and lots of students with the flu. Yuck. But this is much more interesting:

Bouteloua dactyloides (bless you!), better known as buffalo grass:

We’ve recently added a 1-acre meadow to our on-campus teaching and display garden (the Hahn Horticulture Garden at Virginia Tech).

Native trees, shrubs, perennials,and grasses surround a central lawn of buffalo grass. As one of the components of tall- and short-grass prairie, it is a popular forage in the west and midwest. Toughness and no-mow-ability makes buffalo grass a candidate for the low-maintenance lawn. We chose the cultivar ‘Bowie’, which has been reported as a good choice for the Mid-Atlantic…more cold and moisture tolerant. But it’s not cheap – ran us $15/lb with a seeding rate of 3lbs/1000 sq ft. We ordered 1/4 acre’s worth. Our horticulturist Paul calibrated the spreader not once but three times, and was still nervous.

We’re pretty happy with the progress – it’s filling in nicely after 18 months. Once established, buffalo grass will pretty much choke everything else out, but until then, broadleaf weeds and crabgrass are a bit of a pain. Extremely drought resistant, it also handled this year’s surplus rainfall with no problems.

The best way I can describe it is, er, cute! It’s so fluffy, and forms pet-able 6″ tall tussocks with little seed heads dancing about. One just might, after a hard day of academia-induced anxiety, want to lay down in it and make a “grass angel”.

We’ve already had a light frost, hence the tawny color. This presents a teaching opportunity: most of the turf around here is tall fescue or blue grass – fairly evergreen, cool-season grasses. Buffalo grass WILL turn golden-brown in winter, and we’ll get lots of questions as to whether or not our meadow is “dead”. No, it’s just resting!

If you’re thinking of trying buffalo grass or something other than run-of-the-mill turf for your lawn (or even ripping it out altogether), check out ideas from Susan Harris and friends at www.lawnreform.org

RAWRRR!

Posted in honor of Garden Rant’s Halloween-related garden photo contest.

Pick me, Amy, pick me!!!

Now For The Scary Part

This little dude is the Florida Semaphore Cactus, native only to hardwood hammocks in the middle and lower Keys. According to the Center for Plant Conservation, “Opuntia corallicola may very well be the most endangered plant in the United States.” Only one wild population remains (eight individuals), plus a few sites of re-introduction. Loss of habit and an exotic cactus moth have contributed to the demise of this most personable of cacti.

Arbitrary travel tip: I snapped this photo during a recent visit to the fabulous Key West Tropical Forest & Botanical Garden. Please pay them a visit if you’re ever in the vicinity – they are doing so many great things, with so little $$$, as is the case for many small public gardens. And then head straight to Kelly’s on Whitehead Street for outstanding $3 margaritas…served in a pint glass!

Baring it all, again.

Earlier in this blog we had a rather robust discussion about the merits of transplanting trees bare-root. Bare-root transplanting has had a renaissance in arboricultural circles, based in large part on the work of Dr. Nina Bassuk and her colleagues at the Urban Horticulture Institute at Cornell.

As our bloggers noted, transplanting trees bare-root has advantages over balled and burlap trees (larger portion of the root system stays with the tree) and over container-grown trees (more natural root system development). One disadvantage of bare-root trees is the need to protect roots from desiccation during storage and handling. Also, some trees respond better to bare-root treatment than others. Nevertheless, I think we will continue to see increased interest in bare-root planting. One notable trend is planting relatively large-caliper (4” and larger) trees bare-root. This phenomenon has coincided with the development of the air spade, a tool which produces powerful a jet of air that allows arborists or nursery workers to carefully excavate an entire root system with minimal disturbance. Unlike digging a tree with a traditional tree spade, the air spade allows nursery workers to maintain virtually the entire root system when lifting a tree. Last week, my esteemed colleague, Dr. Tom Fernandez, and his Nursery Management class at MSU worked with Paul Swartz, MSU campus arborist, to lift a 10” caliper weeping white pine from our campus nursery. Members of the class took turns using the air spade to excavate the entire root system of the pine. Since the class is divided into lab sections that meet throughout the week the process was spread over several days. After each lab period exposed roots were covered with wet burlap to prevent drying. By the end of the week the tree was ready for lifting and was transported via flatbed truck to its new home at the front entrance to the MSU Horticulture Teaching and Research Center. Paul Swartz reports that he has successfully used the air spade to move several large specimens on campus and the technique is especially useful for moving trees from tight spots that can’t be reached with a mechanical spade. As more and more arborists acquire air spades look for this technique to become more common.

NOTE: Photos courtesey of Dr. Tom Fernandez.

The air spade uses a stream of compressed air to excavate roots.

Note the extent of the root system. A 90″ mechanical spade would have missed at least half the roots of the tree.

Once the roots are excavated the tree is ready for lifting.

The pine resting comfortably at its new home.