Cold Stratification for seeds

You may think of spring as the time for seed sowing, but I do a lot of seed planting now, in the fall. The reason is that most of the cold hardy perennials, trees and shrubs that I like to grow produce seeds that require cold stratification.
This simply means that they require a period exposed to cold temperatures while the seeds are moist and hydrated before they will germinate.

The requirement for cold is a pretty straight-forward adaptation to life in cold climates. Seeds that ripen in the summer and fall might not have time to get established before winter if they germinated right away. The requirement for cold means the seeds don’t actually sprout until spring, giving them a full growing season to get ready for the next winter.

seedbed
An outdoor seed bed is an easy way to stratify seeds

You can — and I used to — give seeds this cold period in the refrigerator. Three months in the fridge in a plastic bag with a damp paper towel to keep the seeds moist is long enough for most everything, though the exact period of cold required varies by the plant. The fridge works, but I think it is way easier to just do it outside. So the past few days I’ve been busy sowing seeds out in my outdoor seed beds. They’re just raised beds, filled with potting media, and covered with a screen lid to limit the number of weed seeds that blow in and keep disruptive animals out. I plant my seeds in the fall. Come spring, after the seeds have had their dose of cold, they sprout.

Dianthus seedlings ready for transplanting
Dianthus seedlings ready for transplanting

Once the seedlings have grown on a while, I dig them out, separate the individual plants, and put them out into their final locations in the garden.

Individual seedlings separated and ready for planting
Individual seedlings separated and ready for planting

I do this with more and more seeds every year, even for perennials that don’t require a cold period to germinate, simply because it is so easy. No fussing around with lights or checking the calendar or even much watering. Just plunk the seeds in, and dig out the plants once they are big enough.

Easy Overwintering

I love growing tender plants as annuals over the summer. But I don’t like buying them again every year, so I try to overwinter as many as I can indoors once frost threatens. However, I have pretty limited windowsill space, so I can’t keep many plants in active growth all winter. Luckily, I’ve found a simple hack that works for a surprising number of plants.begoniaoverwintering

The above begonia is on a high dark shelf. It will sit there all winter, getting essentially no light, and I won’t water it. All those leaves will drop off, leaving nothing but dead looking stems. But come spring, when I put it back outside and water it again, new leaves will start growing and it will come right back.

Quite a lot of tender plants can do this. Just keep them dry, preferably on the cool side (unheated basements are perfect), and they’ll go dormant, usually dropping their leaves, and wait patiently for spring. I personally have done this with both cane begonias (as pictured) and the rhizomatous rex begonias, pelargoniums (the annual “geraniums”), and lots of succulent plants like agaves and cacti. I’ve seen first-hand other people using the same method with great success with brugmansia, bananas, and tender shrubby hibiscus. It seems like it is works most often with plants with thick, woody or succulent stems, but I keep trying it with new things and being surprised when they come through just fine. So if you’ve got some cool tender plant you’d love to over winter, but no window space left, shove it in the basement and see what happens. If it comes back fine in the spring, please comment on this post so the rest of us can learn from your experience!

— Joseph Tychonievich

Pretty in Pink

It’s October. Fall is such an underrated time in the garden, and much pink can be found. In fact, flashes of pink are everywhere!! Got my ma’ams grammed last week; thanks for the reminder, NFL.

Muhlenbergia ‘Pink Flamingo’.
Aye yi yi. Alleged hybrid between M. capillaris and M. lindheimeri. Five feet tall and as wide, huge plumes of pink. Looks like nothing important the rest of the year, then, blammo!!! Sorry, folks north of Zone 6. Actually, it only works here  (Z. 6a) because of outstanding drainage; it’s planted in a pile of gravel. Mine has lived through two winters with -20 F days.  Place where the sun will rise or set behind it for maximum effect. Bunny the Whippet not included.

muhleypinkflamingo

Salvia involucrata – Rosebud Salvia
Big ol’ gal that will not favor you with blossoms until September. Absolutely not hardy here, or anywhere north of Zone 8.  Take cuttings, ’cause baby she’s worth it. The furry, hot pink flowers will thrill any hummingbirds left zipping around (I read ours the riot act this weekend, they have GOT to hit the road soon). Note there is some hullabaloo as to S. puberula vs. S. involucrata vs. some hybrid amongst the two.  Will report back.

salviapink

Chrysanthemum x whatever ‘Venus’ .
Am so tired of the taxonomic uncertainty. ChrysanthemumDendranthemum…  Whatever you call her, ‘Venus’ is a wonderful “real” garden mum (not those heinous meatball things) that brings the pink blooms in September, then fades to palest of pink, but not before every bee in the neighborhood visits.  Fairly compact (2-3’) and pretty darn hardy (Zone 5). Tuck Venus amongst things you know will be done before fall – bee balm, phlox, etc. to keep the show going!

chrysvenus

So there you have it, some pink for our October gardens.  In loving memory of my sister Carlene.

Fall is for Planting…Ornamental Grasses! But so is Spring…

I’ve written previously of my adoration for ornamental grasses.  A few of you folks in the mid-Atlantic might have heard my “Grasses for the Masses!”  presentation complete with lots of arm-waving. As with most of my talks, there’s usually some sort of interpretive dance involved.

Most of our warm-season ornamental grasses are in full gloriousness at the moment.  Because it’s autumn! ‘Tis the season to purchase, plant, and enjoy ornamental grasses!

Pennisetum 'Karley Rose' - available at a garden center near you!
Pennisetum ‘Karley Rose’ – available at a garden center near you!

Well, not really.  If you’d have purchased and planted them in April or May, you’d only have to do the “enjoy” part now.  And your local grower/garden center would LOVE you for it. But most gardeners overlook containers full of  6″ tall Fescue – which is what a LOT of our best grasses resemble in the spring.  It’s always been challenging to sell “green” in the spring – consumers want to see and buy plants in flower – so nurseries and greenhouses that supply garden centers do their darnedest to provide said blossoms.

Gorgeous grasses at Babikow Greenhouses near Baltimore, MD.
Gorgeous grasses at Babikow Greenhouses near Baltimore, MD.

So we pass over pots full of green grassy things in favor of enticing blooms. Nurseries have picked up on this – many include grasses in their summer/early fall production schedule, making full, fluffy pots for the autumn gardener.  This works o.k. for shorter, compact things like fountain grass, little bluestem, etc.   But by September, majestic switchgrass, big bluestem, and the like rarely look that fabulous in a one or two gallon pot – the proportions aren’t right; a bit of wind and rain and the situation is ripe for floppage (closely related to splayage). So you’ll probably pass them over. Again.  Or maybe…take a second look? Just cut them back and plant away – you’ll enjoy them NEXT fall.

Puya report!

For all five of you that might have paid attention to my posts on the genus Puya (which does in fact rhyme with booyah…thank you my west-coastie friends):

Here’s the update that you’ve been waiting for!

Puya is a horrifically spiny, painful, and hateful genus in the Bromeliad family. Native to the Andes, the fish-hook-like spines snare passing mammals; the rotting flesh provides nutrients to the exceptionally lean soil of the arid steppes on which it sort of grows/becomes grumpier.

Puya flowers once an eon, in a spectacular [but ill-earned] display that turned me to mush, based on a photo in an Annie’s Annuals catalog (see my “eternal gardening optimist” post). Autumn of 2012, I ordered and received one healthy Puya berteroniana in a 4” pot. Heckling commenced.  Overwinters in a 40 F greenhouse, where it was watered once or twice. Summers have been spent on our deck. Osmocote has hopefully provided required nutrients. Expected to kill her within months, as it is SO VERY not native to the verdant and humid Blue Ridge mountains of Southwest Virginia.

Happy and amazed to say Pootie [what was I going to name her? Bert??] is in her 3rd year – continuing to grow, and, AND, captured her very first mammal!

Pooyah!

Okay… so it’s a fluffy stuffed possum, and the dogs dropped it from the deck above. But snagged! You know Pootie got a thrill…

It’s the Next Best Thing Since Draft Beer: New Plants and Their Proper Evaluation

'Graham Thomas' rose
‘Graham Thomas’ rose

With many new nursery catalogs arriving in my mailbox at work for 2016 introductions, I thought I would focus this blog on “new” plants. With all the publicity and marketing that goes on for new plant introductions, you would think that they are the next best thing since draft beer or even bread! I am a bit cynical and question whether these new plants really live up to their performance expectations and ornamental attributes. With so many new hydrangeas, coneflowers, coralbells, spireas, etc. released each year, you may ask why am I so cynical? Why would I not jump on the bandwagon and promote all of these new plants like so many garden centers are doing across America? Let me explain.

A decade ago, I conducted research trials evaluating 20 new or recently introduced cultivars of “hardy” shrub roses, many of which are not even on the market anymore. I chose three locations in the state of Wisconsin, each having their own unique soil types, pH, soil drainage and fertility, rain/snowfall and cold hardiness zones. I replicated each of the 20 cultivars ten times at each location and arranged them into blocks with each cultivar represented in each of the ten blocks. The roses were randomly selected for each block and planted, mulched, watered with an application of a slow-release fertilizer. Plants were watered for the first year only as needed. To properly analyze plants for various traits, I allowed the roses to establish for a year with evaluation initiated the following spring. The only care the roses received the remaining years were application of a slow-release fertilizer, weeding and pruning of dead wood following winter. I was trying to replicate conditions that are common in most landscape settings. I did not spray any insecticides or fungicides to any of the roses, regardless of how bad they may have looked due to pests.

After the first winter, I evaluated the roses for winter injury, which they all experienced. The roses were all on their own root systems so if they died back significantly, the new growth would come from the same root system and produce flowers that spring. To some extent, they all grew, though voles killed some of the roses. After the roses starting growing, I evaluated them monthly at all three locations for insects and diseases as well as flowering (amount, size, duration of bloom, etc.). I also measured the plant’s height and spread. A few roses had good fall color. The first year of the trial, the roses all bloomed prolifically. So, one would think that all 20 cultivars are ideal. Not so fast, or “but wait, there’s more” as the television salesman would say to viewers in TV land about a new product. The “real” evaluation started in year two.

In year two, amount of dieback and winter survivability was recorded. To my surprise, the roses in the zone 3 location (boy, that’s cold) had better winter survival than the roses in my zone 4 and 5 location! This is due to consistent and significant snowfall in the most northern location compared to sporadic snowfall and lower amounts in the other two locations. I also evaluated the roses during the summer and fall for flowering, pests, and hip production. Contrary to the catalogs, many of the roses had hips, but some of them never colored up before the cold temperatures arrived at the three locations. Flower production was cited as being continuous all summer by their introducers, however, this was not true for some of the cultivars evaluated. Disease resistance was the most alarming quality I evaluated with many of the so-called “disease resistant” roses being the exact opposite. I explain all these variables to demonstrate what is involved in proper plant evaluation. For a complete report of my rose research trial, see: Jull, L.G. 2004. Hardy Shrub Rose Research Trials. Combined Proceedings of the International Plant Propagators Society vol. 54:429-434.

Knockout® rose is very disease resistant with non-stop blooms, but not hardy in zones 3-5 without significant winter protection Photo credit: http://www.gardeningknowhow.com/wp-content/uploads/2011/08/knockout-rose-400x600.jpg
Knockout® rose is very disease resistant with non-stop blooms, but not hardy in zones 3-5 without significant winter protection Photo credit: http://www.gardeningknowhow.com/wp-content/uploads/2011/08/knockout-rose-400×600.jpg

Now, you may ask, “Why are these new plants, including roses, promoted by these large nurseries as being the best plant around when in effect, they are not?” Many new introductions are from nurseries that trial their plants in their location only. So a plant that performs well in the state of California might not perform the same in Michigan and vice versa. There isn’t the scientific rigor applied to these new plant evaluations that would occur by non-biased, university researchers who have no stake in selling or promoting plants to the public. This is where the beauty of applied, scientific, university-based studies can play a huge role.

Also, these new plants should be evaluated over numerous years, at various locations/soil types, climates, with appropriate replications of each new plant in a random arrangement (not all planted together). This type of quality research is done by a few large nurseries but it is seldom done this extensively by others anymore as demand for new plants is never satisfied and the cost of trialing over several years and locations is too costly.

Unfortunately with increased costs and significant budget/program cuts, most university research is now geared toward larger, basic science studies that have high indirect costs built into the grants. These funds, usually 50% or more of the grant total, go directly to the university to cover overhead. The researchers do not see or can use overhead funds. Ornamental plant evaluation research is now considered either non-fundable by granting agencies, not “scientific or scholarly” enough by their own departmental colleagues or provide significant overhead funds back to the university.

Some researchers rely on their various nursery and landscape associations for small amounts of research support, while others try to piece meal together small amounts of research funds. With the increasing costs of land (yes, we do have to pay for research space at university research stations), plants (not all are freely given to the researchers), labor, supplies, etc., it is becoming critically important to seek alternative funding sources as most federal and state granting agencies do not fund ornamental plant evaluation research. Many of the new initiatives for federal grants seek to fund food crop based research, especially in organic and sustainable food production. Applied ornamental horticulture plant evaluation research at universities has plummeted with most new plant evaluations conducted by the large nurseries that introduce these plants.

There is another source for evaluation of these new plants. Various arboreta and botanical gardens around the U.S. are conducting evaluation trials. I am a fan of these studies as these gardens and evaluators are also not in the business of selling plants and can provide some analysis, though it is usually only at one location. Richard Hawke, Chicago Botanic Gardens Plant Evaluator and Horticulturist, has done an excellent job of evaluating many species of herbaceous perennials and a few woody plants. He publishes Plant Evaluation Notes: (http://www.chicagobotanic.org/research/ornamental_plant_research/plant_evaluation), a series of wonderful publications that help both the amateur and professional gardener to choose appropriate plants for the Upper Midwest. There are other botanical gardens and arboreta that do the same, with evaluations based on their local climatic conditions. I often rely on Mr. Hawke’s recommendations when choosing herbaceous perennials in my Wisconsin garden and have yet to be disappointed.

Chicago Botanic Garden Plant Evaluation Notes Source: chicagobotanic.org
Chicago Botanic Garden Plant Evaluation Notes
Source: chicagobotanic.org

So the next time a new plant comes across your way, think twice before buying it. There is the philosophy “Buyer Beware”, and I do recommend people to buy plants, but instead of buying 10 of one cultivar, try one or two of the new plant and make a judgment call the following year or two after you planted it. This is especially important for landscapers who design and plant large amounts of plants. You might be surprised to see the “best thing since draft beer” plant being anything but that. As some of us know, there is nothing better than draft beer (or whatever beverage you really like).

Laura Jull, Ph.D. aka The Lorax

Perennial Funday: Eriogonum allenii ‘Little Rascal’

I’m going to keep posting about perennials that deserve more attention until somebody makes me stop. The fact that my subject is, once again, yellow… is merely coincidental

Definitely was a crowd favorite during the Perennial Plant Association annual Symposium’s grower tour (mentioned in my previous post).  These photos were taken at Emory Knoll Farms north of Baltimore; I believe that they were trialing and/or including it in their plant selection for green roof use.

Eriogonom allenii 'Little Rascal' at Emory Knoll Farms
Eriogonom allenii ‘Little Rascal’ at Emory Knoll Farms

Thanks to Mary Vaananen, Jelitto’s North American operations manager (and goddess of perennial plant knowledge), who just happened to be standing next to it, full of 411, when I squealed “WHAT the (blankety blank) is THAT?!” My compadre Paul Westervelt added more info, as he’s also a plant geek deluxe (and manager of the annuals and perennials section of Saunder Brothers Nursery). D’oh. Plus you rock gardening fanatics probably know this cutie as well (I may have first seen this in one of Joseph T.’s talks, now that I think about it).

Eriogonum allenii, shale barren buckwheat, is native to counties that comprise the Virginia Highlands plus those on the West Virginia side of the line in the same region. Within these counties, the scattered populations reside in the botanical wonderlands called the shale barrens.

This floriferous selection ‘Little Rascal’ is indeed from Jelitto, so you too can obtain seeds of this rarity (along with detailed germination/growing instructions). Jelitto lists hardiness to USDA zone 5. As with most species from the barrens, it requires plenty of sun and excellent drainage.

Flowers you can hear!
Flowers you can hear!

Stocky and slightly shrubby in habit, the coarse grey-green green foliage was, when I saw it at the end of July, completely smothered in deep gold flowers. Simply gorgeous.  It was abuzz with bees of all sorts, including insanely happy honey bees that could barely attain lift-off.  I have a plot of regular-old-buckwheat (same family, Polygonaceae), but our spoiled-rotten bees always seem underwhelmed.  Wait till they get a load of this!