nurseries – The Garden Professors™

Go sport fishing at your local nursery

Regular fishing, for actual fish, is quite possibly the second most boring think ever invented (First place, of course, goes without question to baseball) but sport fishing! Now THAT is something I can get behind.

By sport fishing I mean, of course, looking for sports – chance mutations – in plants. Sometimes a flower color changes, or sometimes a leaf becomes variegated, like on this lilac branch I found at a friend’s nursery a couple years ago

Nurseries are great places to go “fishing” for these sports, simply by walking down the rows of plants looking for anything odd or out of place. Sometimes they are true sports, and sometimes there has been some hanky panky… Last summer I was walking through a nursery looking at their pots of blooming Sweet William (Dianthus barbatus)

sweetwilliam

And suddenly I noticed a plant that was markedly different. dianthus hybrid

Way too different to just be a sport, this was a chance hybrid with… something. What, I don’t know, Dianthus is a big, promiscuous genus, but I like it and snatched it up. The chance hybrid was pretty enough and intriguing, and after blooming it produced a healthy crop of seeds, so I grew some out. One year later, they’re blooming in all sorts of interesting ways..

One looks just like a regular Sweet William, but significantly shorter

dianthusf22

Another is a nice red, though the flowers are a bit sparse

dianthusf23

And this one, my favorite, has decided to pretend to be a carnation with masses of double, fragrant flowers.

I, of course, have responded by collecting many many more seeds from that original chance hybrid picked up at the nursery, and can’t wait to sow them out and see what else may show itself.

So next time you at a big nursery, take some time to go fishing for sports and hybrids… you may just find something cool.

— Joseph Tychonievich

Buying locally-grown plants

Of course we want to buy locally-grown plants! There are a gazillion sound reasons to do so. In a paper that may be from near here, or not, I perused the gardening column over Sunday coffee, written by (a human) (name withheld to protect the very, very nice and usually accurate author). But in this particular article, the writer ventured deep into huh? territory.

And that territory is my area of expertise: nursery and greenhouse production and marketing. My favorite talk to give to gardening groups is “From Grower to Garden Center.” As the Garden Professor Least Likely To Get Riled Up, it pains me a bit to even bring this up when someone’s willing to crank out a column week after week. Heck, I haven’t been able to write anything lately, accurate or otherwise. The bulk of the article was correct and positive, plus promoted a great local grower (of which we have very, very few), BUT there were a few statements made that I thought might make good points for clarification (teaching moments) and maybe generate some discussion.

“Just like locally grown food, a locally grown plant is going to be much easier on the environment. Transportation and fuel costs are lower, and carbon footprint emissions are decreased. Plus, without a need for the special packaging to ensure a safe journey across the country, less packaging ends up in a landfill.”

I’ve unloaded plenty of trucks – the only things that use any “special packaging” are poinsettias and sometimes florist mums – sleeves and or boxes. “Cross-country” is rarely the case, even for big box stores – they work with regional growers (albeit large ones) for annuals and perennials. However, the writer’s point is well taken in that even here in the “far east,” some independent garden centers and big box stores get shrubs and trees from the west coast (Monrovia must give them a heck of deal). One of our two local garden centers carries Japanese maples from Monrovia; this retailer is located less than 10 minutes from a nursery that specializes in Japanese Maples. Go figure.

“Beyond the environmental impact, when you buy a locally grown plant you usually are buying a healthier plant. It will already be accustomed to our native soils and growing conditions.”

“Usually” is a good qualifier here. Regarding health, I’ve seen amazing quality from far, far away, and real crap from a couple local growers. Local does not automatically equate to pest and pathogen free, well-rooted, non-stretched, or any other criteria for quality. The second sentence, however, has haunted me for a week. Nursery and greenhouse plants are grown in soilless media – peat or peat alternatives; pine bark; fir bark; etc. How can that particular plant be accustomed to “our native soil”? To put a finer point on it, what, exactly, IS our “native soil”? Our own 19 acres has yellow clay, red clay, forest duff, sandy loam, loamy sand (I made that one up), and everything in-between.

Regarding growing conditions, your spring-purchased plant has most likely been in a controlled environment of some degree, whether a greenhouse or coldframe. If I went shopping at any retail greenhouse or garden center (which I probably will do this weekend), I would probably purchase some plants right out of the greenhouse. Of which they are accustomed.

“And, with less travel time, the plant is less likely to be stressed by excessive handling and is less likely to be over watered or over fertilized.”

On the truck, off the truck. Place on retail bench. This is how a plant would be handled whether it was grown by a local wholesale nursery 10 miles away or 1000. How excessive is that? And why would travel time cause over-watering or over-fertilizing? If anything, the inverse is true.

“New gardeners can be assured that they are buying a variety that grows well in our climate, as local growers supply what grows here. The plant will be put out for sale when it’s actually time to plant, not when a buyer across the country wants to sell it to you.”

Grows well? What grows here? I’m not even sure where to begin with that bit of information. Isn’t that part up to the gardener, new or otherwise?

And wherever you may live, I guarantee there were plenty of tender annuals, tomato transplants, and other jump-the-gun goodies available for sale from your local grower or garden center 45 days before your last frost date. What IS true – a good grower/retailer or garden center staffer won’t let you leave without a gentle (or not-so-gentle) reminder to keep ’em in until after last frost. To which I always nod, agree, and then commence with trying to produce the earliest tomato in the tri-county area. Because I’m an expert.
*snort*

A Real, Live, Learning Experience

What a crazy spring! But it finally, finally came here to the Blue Ridge Mountains (Linda Chalker-Scott refers to them “speed bumps”).

My Ornamental Plants Production & Marketing class has been at work since early February, growing plants and marketing them at the Hort Club Plant Sale as part of their lab experience. Of course, they are completely at my mercy as to what they get to grow (bwuhh ha ha *evil hand wringing*). And due to their professor being a complete plant dork, they wouldn’t know a potted mum if it hit them upside the head. Not that there’s anything wrong with mums. But with so much fabulous stuff to choose from – they can just look that mum crop protocol up in a book if the need arises. They do get to experience a few zonal geraniums, but that’s only because the University’s past-President buys 50 red ones from us every year.

So what do they grow? Fabulous goodies you could never, ever find at a garden center in SW Virginia. Variegated Manihot esculenta. Dr. Cho’s newest Colocasia ‘Black Coral’ (gloss black with deep blue veins). Awesome landscape begonias such as ‘Gryphon’ and ‘Santa Cruz Sunset’. Fun annuals like Torenia and Osteospermum. Fifty-two different things – fairly ambitious, considering there are only 11 students. We fill a 40′ x 80′ house plus two “research” greenhouse sections that I commandeer the moment they come available.

My production students always start out the semester rather tentative, and then get more engaged as time goes on. We do a 2.5 day field trip across the state to visit top greenhouses, nurseries, and garden centers in early April. My gang comes home with a real appreciation of the hard work and long hours required to be successful; more important, perhaps, is their exposure to the tremendous passion and enthusiasm of the people in the business, many of who are alumni of our department.

SO…thirteen weeks later, we have greenhouses crammed full of really great plants,a bunch more ordered in from top area nurseries, an enthusiastic mob of customers with pent-up plant lust, and some very proud students.

And that’s the best part – the students get to/have to work with (gasp) the PUBLIC. Very disconcerting for some of them. The Plant Sale Chair for the club, who is also in my class, is a terrific student but a bit shy. Of course, he got the loudest customer of the day. She hollered “Hey, boo boo! Tell me about this plant! Sez here you grew it!” Ten shades of red later… I thought he was going to faint. But he did regain his composure and helped her with some other things. He also made me promise to never, ever tell his classmates what she called him.

But you’re not in my class 😉

Here comes “boo boo” with his very nice Cissus discolor (Rex Begonia Vine).
Names withheld to protect the totally embarrassed.

You don’t have to be crazy to work here, but it helps

Recently I spent a week in Oregon working on a Christmas tree genetics project along with my colleagues Chal Landgren( Oregon State University), Gary Chastagner ( Washington State University), and John Frampton (North Carolina State University). The objective of the project is to identify superior seed sources of Turkish fir and Trojan fir for use as Christmas trees around the United States. We refer to the project as the Cooperative Fir Genetic Evaluation or CoFirGE – remember, the most critical step in any experiment is coming up with a catchy acronym. CoFirGE began with a trip by my colleagues to Turkey where they collected seed from 100 fir trees across a range of sites in Turkey

Turkish fir growing in western Oregon

Why are we interested in these species? Both Turkish and Trojan fir are closely related Nordmann fir, which is widely used as a Christmas tree in Europe. These species make wonderful Christmas trees due to their symmetry and needle color. In addition they may be resistant to diseases, particularly Phytophthora root rot, that plague Christmas tree growers from Washington State to North Carolina.

So, what was going on in Oregon? After the seed were collected in Turkey they were sent to Kintigh’s nursery near Eugene, Oregon, where the seed were sown to produce seedling plugs. The next step of the project will be to send the seedlings out to cooperators in five locations (Pacific Northwest, Michigan, North Carolina, Pennsylvania, and Connecticut). This is tree improvement on a grand scale. In each region there will be two test plantings and each planting will include 30 reps of 100 seed sources or 3,000 trees. Multiplied by 5 regions and 2 plantations that’s 30,000 trees total that we will collect data on for the next 8-9 years.

30,000 seedlings ready to be sorted and shipped

Each seedling is individually labeled with a bar code for identification

Sorting into to boxes to send to cooperators around the country

But step one is getting the seedlings from the nursery to the out-planting sites. That means lots of tagging, sorting, and bagging. With help from technicians and students from WSU, OSU and NCSU and staff from Kintigh’s we were able to get all the seedlings sorted and bagged by mid-day on Thursday and start them on their journey to their new homes. Next step: Planting…

When all else fails…

As someone who has had a foot in Horticulture and a foot in Forestry throughout most of my career, people often ask me to compare the two disciplines. One of the truisms that applies in both cases is, “When all else fails, blame the nursery.” I’ve seen this following seedling die-offs in industrial forest plantations and I’ve seen it many, many times after street tree or landscape planting failures. In fact, if you believe some people, tree nurseries are responsible for every plague and pestilence to ever afflict mankind. Are some tree failures related to things that happened in the nursery? Of course. But there are lots of things that can go wrong between a nursery and a tree’s final destination; and even more things that can go wrong after it’s planted.

I know a lot of people don’t believe this, but nursery growers want their trees to survive and grow well after they leave their care. Growing trees is like making cars and any other business. You need satisfied customers if you expect to have repeat business. The best growers are always looking at their production practices for ways to improve their product. Last week I visited Korson’s tree farm in central Michigan. Korson’s grows Christmas trees and B & B landscape conifers. Rex Korson, the owner, has been concerned over the impact of root loss during transplanting of landscape trees. So much so, in fact, that he is conducting his own trial on root pruning.

For those that are not familiar, root pruning of B & B trees is usually done a couple years before harvest by using a tree spade to severe tree roots. The spade used for pruning is slightly smaller than the one used for harvest, so that new roots stimulated by pruning are harvested with the root ball. Does it work? I did a root pruning trial a few years back to see if it could improve survival of fall-planted oaks and had mixed results. For Rex’s trees, however, the initial results were pretty impressive. In the first photo below are root systems of Norway spruce trees dug with a 30” tree spade. The second photo shows the root systems of trees dug with the 30” spade that had been root-pruned last October with a 24” tree spade. The response in one-year’s time was dramatic. At this point there no out-planting data but, other factors being equal, increasing the amount of roots harvested with the tree should increase transplant success.

I should hasten to point out that Rex is not alone. I work with many other growers in the state that are constantly tinkering with this or that in their production systems; sometimes on their own, sometimes with university specialists or extension educators. I’m not so Pollyanna to think that everything is always rosy in the nursery world but most growers, especially the better ones, are aware of the issues out there and are working to build a better tree.

Spruce dug with 30″ spade without root pruning

Norway spruce root-pruned in Oct 2011 with a 24″ spade and dug Oct 2012 with a 30″ spade.

Close up of new fine roots

Tree spade mounted on excavator for root pruning. With this system an operator can root prune 8 trees in 5 minutes.

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Plant containers – does size really matter?

A few days ago I got a question from Cynthia about “potting up.” For those of you for whom this is an unknown phrase (and no, it’s not a euphemism for a certain herbal activity), it refers to the practice of moving plants into ever larger containers. She was wondering if there was any “real science” behind the practice – in other words, why not just start out with a larger container?

Hah! I needed no further encouragement and spent several days collecting and reading decades’ worth of research. And there is a LOT of research on this topic. As you might guess, it’s geared towards production nurseries and greenhouses. But the good part is that it’s been done on just about any kind of plant material you could want. Vegetables. Annuals. Perennials. Grasses. Shrubs. Native plants. Ornamental, fruit and forestry trees. Seeds, seedlings, cuttings, big plants, little plants. Ahhhhh…data!

Almost without exception, you get better growth on plants grown in larger containers, whether you’re measuring height, number of leaves, leaf area, stem diameter, shoot and root dry and fresh weights, whole plant dry and fresh weight,…you get the idea. This isn’t surprising, because with a larger root zone you can support more roots, which in turn support more above-ground growth.

The only parameters which tended to diverge for some species were flower and fruit production. Restricted roots can stimulate sexual reproduction in plants, possibly because poor growing conditions spur the plant to reproduce before it dies. Other drawbacks include increased probability of circling root systems, and higher ambient soil temperature, compared to plants in larger containers.

Smaller containers might be considered desirable when one is trying to limit above-ground growth – the “bonsai” effect. And they require less water than larger containers – which brings us to the bottom line, as far as production nurseries are concerned.

Larger containers take more space. And water. In at least one study, water costs were shown to be “prohibitive for larger container sizes.” Furthermore, smaller containers are preferred by production nurseries to “optimize production space.” Another economics-based study found that “the smaller of these was the more economical.”

But most of you probably aren’t interested in the economics of plant production – you want to know what’s best for your own container plants, whether they are houseplants or pots of herbs or punches of annual color on your patio. The science is clear: it’s best to pot up plants in small containers quickly into their final destination, rather than making several (pointless) intermediate transplants.

Time for another WOW (Why oh why)!

During my nursery visits this summer I came across Taxodium distichum ‘Peve Minaret’, a dwarf cultivar of bald cypress. I hate it:

Why? Because it’s a crummy specimen. If it’s not quite clear, here is a close up of the double leader:

I’ve ranted a couple of times about the production nursery practice of topping young trees to create fuller crowns (you can see those posts here and here). I’m constantly taken to task for this, with comments along these lines:

1) There’s nothing wrong with it. Customers like the look.

2) After topping the production nursery selects a new leader.

3) If the production nursery doesn’t select a new leader, then the retail nursery should.

4) If the retail nursery doesn’t, then it’s the customer’s job to do it.

5) If the customer doesn’t, then an arborist should catch it.

Somehow it’s always someone else’s responsibility to do the corrective pruning needed to prevent future problems. Yet I have not seen a cogent argument about why this practice is necessary (and “customers like the look” doesn’t count). In fact, a recent email told me I’m approaching this all wrong:

“I think it would be better for you to attack this problem by teaching the maintenance industry on how to remove a few poor branch angles, and make a profit on this, then to tell the consumer that they don’t know what looks good to them.”

Aha. So we get unsuspecting customer to buy a problem tree, then charge them again to fix it!

It’s not like I have to look very hard to find these trees in nurseries. Believe me, they’re everywhere, at least in this part of the country.

So…proponents of this practice. Convince me (1) that there is a valid, evidence-based reason for this practice, and (2) it’s okay for trees like this bald cypress to end up in retail nurseries.

W.O.W. (aka Why oh why do nurseries sell this plant)?

Since we’re back on the alien train (spaceship?), I thought I’d bring up another of my least favorite shrubs – Scots broom – as our next installation of WOW (why oh why?).

Scots (or scotch) broom (Cytisus scoparius) is a much-reviled intruder in the western and eastern United States. Originally introduced as a sturdy ornamental, this legume quickly invaded disturbed areas and is labeled as a noxious weed in several western states. In Washington, it’s quarantined. Research dollars have been dedicated to studying best methods of eradication. So it doesn’t take a rocket scientist (or even a garden professor) to figure out that it’s probably not a wise addition to one’s landscape.

But apparently some nurseries either (1) haven’t paid attention or (2) don’t care. In a quick look at the internet, I found nurseries in many states, including Oregon and California, that sell this species. Many will argue that they are selling “less invasive” or “sterile” cultivars, which is a poor excuse in my opinion. Readers of this blog know by now that cultivars often revert to wild type, and there’s no reason to assume that broom cultivars are exempt from this ability. Furthermore, we know that plants have the ability to extend their ranges past what we think they are (hello kudzu?).

Just popping in to say hello

There are many ornamental alternatives to Scots broom that can easily be found online or in print. I’d love to hear some rational arguments from nursery owners, landscape designers, or anyone else justifying the sale of this plant.

Where to draw the line on a vine

Last week’s column on “why do nurseries sell this plant?” struck a chord with many readers as well as with Holly! So here is this week’s submission: that ubiquitous vine, English ivy.

First of all, we’ll stipulate than many ivies are sold as English ivy (Hedera helix) but may be entirely different species. Genetic research on invasive ivy populations in the Pacific Northwest identify most as H. hibernica (aka Atlantic ivy), with H. helix making up only 15% of the invading populations. Regardless of their species identity, it’s obvious that Hedera is a genus with the potential to escape gardens and invade remnant forests or other environmentally sensitive areas. It grows so vigorously that it can create monocultural mats on forest floors; it grows into trees where its sheer weight can break limbs and in some cases topple entire trees.

But what about other regions of the country – or the world, for that matter? In colder climates, Hedera spp. are much better behaved, dying back to the ground every winter and rarely able to flower and reproduce. The absence of a seed bank means the vine can be kept in check more easily. And it does tolerate tough environmental conditions where other groundcovers might not succeed.

Yet consider another invasive: kudzu (Pueraria montana var. lobata) For decades this noxious weed was thought to be too cold sensitive to expand past the American Southeast. Yet populations have been found in Maine, Oregon, and most recently in Ontario, Canada. Plants adapt!

So – is it worth the risk to buy a plant known to be invasive elsewhere, simply because it’s not a problem yet?

And why oh why do nurseries in Washington state continue to sell Hedera spp. as ornamentals?

Why do nurseries sell this plant?

I wish I were more like Holly…wandering around nurseries finding pretty and unusual annuals and perennials to get excited about. Instead, I seem to gravitate to plants that annoy me.

Today while looking for some trellises (for those containerized Clematis vines that I’ve been torturing) I saw pots of the Equisetum hyemale (“a tall, evergreen, spreading, reed-like grass”) for sale:

As readers of this blog surely know, Equisetum spp. – or horsetails – are not grasses but primitive relatives of ferns. That taxonomic blunder aside, the thought of deliberately planting any Equisetum species in a landscape sends shivers down my spine.

Now E. hyemale is not as weedy as E. arvense, but in nearly every seminar I give on controlling weeds with mulch someone asks about getting rid of horsetails. Short answer – you pull. And pull and pull. There’s no good herbicide for them, nothing seems to eat them, and they spread aggressively.

And speaking of eating, did you know that horsetails are poisonous? They contain an enzyme (thiaminase) that deactivates thiamin (vitamin B1) in the unfortunate consumer’s body. The most common victims of horsetail poisoning, ironically, are horses. Horsetails are considered noxious weeds in pastures used for grazing – and yes, they are native to the United States.

Sure, horsetails are interesting looking plants. But do you really want something in your garden that the production nursery describes as having “indefinite spread?” And how does keeping them in a pot, as one production nursery recommends, keep them from spreading spores? Especially if you plant them “in or around ponds and streams?”

I just think this is such a bad idea for home landscapes. Even if it is a native species.