Over the last couple of weeks I’ve been in London having some unforgettable garden experiences. Thanks to the generosity of my UK colleagues Glynn Percival and Jon Banks I was treated to Kew Gardens, RHS Wisley Gardens, and Windsor Castle. I hope to construct several blog posts from these visits, but today’s post is an homage to the English garden meadow. Instead of monocultural turf lawns, mowed and sprayed into submission, why not consider a more biodiverse and visually pleasing approach to groundcover?
As the title of this post suggests, this is not a new topic in our blog. (You can read other related posts here, here, and here.) What was so stunning about these garden meadows (meadow gardens?) was the scale and effortless beauty. For instance, consider this tree-lined parkway at Kew, covered with English daisies.
I saw my first honest-to God cowslip in a meadow garden at the British Museum of Natural History.
How about these adorable tiny daffodils and checker lilies?
And here they are en masse.
This isn’t to say that the formal lawn isn’t a thing in England, It is.
But unless you have a castle, a baseball diamond, or a putting green to manage, why not consider something more appealing, not only to the eye but to your beneficial wildlife?
In most parts of the country it is time to dust off the seed starting trays, pick out your favorite seeds, and get a little plant propagation going on. There’s definitely a lot of science (and perhaps a bit of art) to successful seed starting. While the process starts (and relies on) the imbibition of water, one of the biggest factors that affects the success, efficiency, and speed of seed germination and propagation is temperature. Germination relies on a number of chemical and physical reactions within the seed, and the speed and success of those reactions is highly temperature dependent. Respiration, where the seed breaks down stored carbohydrates for energy, is probably the most notable process involved that is temperature dependent (source). Think of it in terms of a chemical reaction you might have done back in your high school or college chemistry class – there’s an optimum temperature for the reaction and any lower and higher the reaction might slow down or not happen at all.
Thinking of it this way, seeds and germination are just like Goldilocks and her porridge – there’s too hot, too cold, and “just” right. Seeds are the same way – there’s a “just right” temperature for germination. The seeds of each species has a different optimal temperature for germination with a range of minimum and maximum temperatures for the process.
Why is important that seeds are started at their optimal temperature?
The optimal temperature is the one at which germination is the fastest. This may seem to only have consequences for impatient gardeners, but slower germination speeds increase the days to emergence for the seeds, which in turns means that the seeds and seedlings have a greater chance of failure. The early stages of germination are when seedlings are most susceptible to damping off, which can be caused by a number of fungal pathogens (Fusarium spp., Phytophthera spp., Pythium spp., etc.) that basically cause the seedling to rot at the soil level. These pathogens (as well as decomposers in some cases) can cause seeds to rot or decompose before emerging as well. That’s why you’ll sometimes see seeds that are slow to germinate (or traditionally direct sown like corn, beans, and peas) treated with those colorful fungicides. The fungicide gives the seed and seedling a little bit of protection (for a week or so, depending on the product), which is handy if you accidentally sow them before soil temperatures are optimal or if the species is slow to germinate.
If emergence is really slow, there’s also the possibility of stunting or failure due to exhaustion of the stored carbohydrates that the seed relies on until it begins photosynthesis. So the closer to the optimal temperature the seed is, the faster the emergence and the highest percentage of germination success.
What does this mean for home gardeners?
Whether you are starting seeds indoors or direct sowing outdoors, knowing the germination temps can help increase your likelihood of success. You can find a variety of resources for the optimal germination temperature for your selected crops. In general, most warm season plants, like tomatoes, peppers, and summer flowers are in the 70-80 °F range. This is why most of the warm season crops are started indoors – so temperatures can be controlled to higher levels.
Many of the cool season crops germinate at much lower temperatures, which means many of them can be directly sown early in the season rather than started indoors. Crops such as spinach, lettuce, and other leafy greens have these lower germination temps and typically perform better if germinated at lower temps.
It should be noted that this is for the soil temperature, not the air temperature. If you’re starting seeds in your home, most people don’t keep their homes in the 75 – 80 degree range in the winter. Many commercial operations use warmed tables or beds for seed starting, rather than heating the whole facility to the necessary temp – it would be expensive. For home growers, supplemental heat mats can help increase soil temp without having to heat a whole room. In a pinch, you can even clean off the top of your fridge and keep seedlings there. It is higher up in the room (heat rises) and most refrigerators create some amount of external heat as they run.
For any seeds that you’re direct sowing outdoors, whether they require higher or lower germination temperatures, you’ll have more success if you plan your sowing around soil temperatures rather than calendar dates (planting calendars can be good for estimation, though). Investing in a soil thermometer can offer detailed information on the specific temperatures in your garden soil. Or, if you have a good weather station nearby many of them have soil temperature probes that could give you a good idea of what the soil temperatures are in your region.
But don’t let the cool/warm season crop designation fool you – the Cole crops like cabbage and broccoli actually have an optimal germination temperature on the warmer side, but grow better in cooler temperatures to keep them from bolting (flowering). This is why they need to be started indoors for spring planting, but you can start them outdoors (even trying direct sowing) for fall crops – they germinate in the heat and then slow growth as the temperatures drop.
We’ve discussed barerooting/rootwashing trees before, and research on this controversial topic continues. But what about smaller shrubs and woody perennials? What about herbaceous perennials? Basically, what about PERENNIALS???
I’ve always made a practice of rootwashing everything except for annuals. They don’t last long enough to suffer the perils of potbound plants. But many gardeners are nervous about disrupting more fragile root systems. Let’s see what happens when we do.
A little context: we’ve just moved to our family farm, which has AMAZING spring flowers that the bees love. But once those are gone…there’s nothing. I was desperate to provide some food for bees and butterflies, so it was off to the nursery to shell out a few hundred bucks for the beginnings of our south-facing pollinator garden – a previously barren spot left after construction of our porch.
So I bought Lavandula stoechas ‘Bandera Purple’ and ‘Winter Bee’, Salvia ‘Caradonna’, Agastache ‘Acapulco Deluxe Red’ and ‘Blue Boa’, Erysimum ‘Winter Passion’, Verbena ‘Homestead Purple’, and Lobelialaxiflora. I depotted and soaked them in a water bath, using a gentle hose setting to loosen up media in the center. For most of these plants, a massive root disk at the bottom of the pot had to be cut off like a giant slice of salami. If necessary, I “tickled” the remaining rootball to work out the rest of the media.
Here is Erysimum ‘Winter Passion’ potted, depotted, and washed.
The Agastache and Verbena cultivars were also in pretty good shape, much like the Erysimum. Just a gentle washing and tickling was enough to remove all the media and reveal the roots.
Here is Salvia ‘Caradonna’ potted, depotted, and washed, and Lobelialaxiflora potted, depotted, and washed.
Apart from the root Frisbee on the bottom of each pot, the roots were confined to the center of the pot, pretty much where they had been in their previous container. So question number one for all of you gardeners – why would you want to dig a hole to plant all of that media (which is nothing like your soil)? My answer – you don’t! Keep that good organic material as part of your topdressing.
Here is Lavandula stoechas ‘Bandera Purple’ potted, depotted, and washed;
and here is Lavandula stoechas ‘Winter Bee’ potted, depotted, and washed.
I have to take time out for a special rant about the lavenders (retailing at $19.99 and $12.99). Look at the root mass of the ‘Winter Bee’. It’s entirely unacceptable. The woody roots are in the shape of the liner pot from transplants past. News alert: these systems do NOT self-correct. They must be straightened or pruned to regain a natural structure. The ‘Bandera Purple’ – the more expensive of the two – was actually three plants in one color-coordinated bowl (“Go ‘Colour Crazy’ with matching pots and flowers”!). Fine by me – I just got 2 free plants. (By the way, this is nothing new for me – I’ve written about it previously here and here.)
Another upside is that hole digging was short and sweet. Holes were just deep enough to accommodate the root mass and wide enough to allow roots to be spread. Soil was added and watered in. The leftover organic media was used as the first layer of topdressing, followed by a fresh woodchip mulch. And then irrigation to soak the mulch well.
It’s important when you rootwash plants to provide optimal soil water every day, particularly when it’s hot and sunny (as this south-facing garden is). Even with the gentlest root washing there will be a loss of fine roots. But the continuity of the soil system means that the soil around the roots will be just as moist as the rest of the bed. Roots left in soilless media quickly dry out. Yes, I had afternoon wilt on many of the taller plants during the first week or so, but they recovered every evening. The wilt has become less noticeable since then.
So here’s how they look 3 weeks after planting (sunny day, about 80°F). And I’m happy to report that not only birds and butterflies but hummingbirds have been visiting our pollinator oasis garden. And all those single photos scattered through the post? They are all close-ups from this garden – taken just minutes ago.
(Question number two for gardeners – what are you waiting for?)
(posted by Holly Scoggins)
The Perennial Plant Association (PPA) is a unique group of folks – comprised of plant breeders, educators, propagators, promoters, garden writers, growers, retailers, gardeners, and landscape designers – all under one umbrella. The PPA is probably one of the most vertically-integrated plant organizations out there. If it has anything to do with a perennial plant, there’s a good chance one of our members is involved.
The marvelous/legendary PPA Symposium has been held in all parts of the country. This year’s perennial-fest is in Raleigh NC. This goes back to my particular roots with the organization – my first PPA experience was in 1997 symposium, also in Raleigh, while I was grad student at NC State. Helped out in a few capacities, including tour bus wrangler (on the surprisingly rowdy bus, no less).
A special feature THIS year in Raleigh will be a one-day plant-geek-fest, open to the public as a separate registration item (of course any perennial freaks are absolutely welcome to attend the entire week of symposium events as well!).
Many/most of you are not located in the Mid-Atlantic/Southeastern region of the U.S. So why I am I touting this here? Because some of my biggest Ah-Ha! moments regarding growing and gardening have happened in places far from my comfort/hardiness zone. And the plants…oh the plants. In searching through my older GP posts, I’ve mentioned the PPA at least 9 times.
Recent examples: In 2016, the PPA symposium was in Minnesota… really opened my eyes, heart, and wallet to some lesser-known prairie species and design concepts. I probably have one of the larger Silphium collections in Southwest Virginia now. Whoops.
Last year’s symposium in Denver, Colorado brought with it awesome alpines and steppe plants – many of which I could grow here, with a bit of assistance from enhanced drainage. Of course there were also examples galore of rock gardening techniques to help make that “enhanced drainage” thing happen. Beyond the plants and gardens, another highlight is the opportunity to meet the area’s botanical movers and shakers that I wouldn’t have had otherwise. So much positive, fun energy – helps to remind me why I do this thing!
So…trust me when I say driving for 6-8-10 hours or hopping on a plane to the handy-dandy RDU airport will be WORTH IT. Especially if you stick around for core symposium including fab tours to private and public gardens, independent garden centers, behind-the-scenes at wholesale nurseries, and (wait for it) dinner and garden wandering/shopping opportunities at Plant Delights Nursery.
Back to the “Spend the Day with Perennial Plants” opportunity on Monday, July 30 – Check out this lineup for the plant talk day – and note the geographic diversity of the speakers – again, this isn’t just a “Southeast” thing!
– Patrick McMillan is an Emmy Award-winning host, co-creator, and writer of the popular nature program, Expeditions with Patrick McMillan . He’ll highlight Carolina native perennials for the garden in a morning talk. Later that afternoon, he’ll cover Southwestern plants we can use in the Southeast to cope with drought.
– George Coombs manages the horticultural research program at the Mt. Cuba Center in Hockessin, Delaware. This renowned botanical garden focuses on native plants, and their plant evaluations are making a big splash in the industry. Get a peek at the top-performing selections and find out what it takes to stand out in their trials.
– Christian Kress owns a specialty nursery in Austria that focuses on rare perennials from around the world. He’s traveled extensively, authored books, and introduced several beloved perennials to the market. He’ll bring the knowledge on flocks of Phlox (!) and introduce us to the amazing selections coming out of Russia.
– Judith Jones owns Fancy Frond Nursery in Gold Bar, Washington. She’ll open the world of ferns and inspire a new appreciation for their role in the landscape. [Am hopeful that frond puns will abound.]
Other presentations include iris breeder Kevin Vaughn; John Kartesz on native plant inventory software that generates customizable maps and databases; Larry Mellichamp on the world of unusual, surprising and bizarre plants; and Lauri Lawson on medicinal plants.
ALL THIS IN ONE DAY, PEOPLE.
The whole shebang takes place at the Hilton North Raleigh/Midtown. Advanced registration is required and early bird pricing ends June 1. See the program description and get registration information on the PPA Raleigh website. Be sure to check out the glorious e-Brochure just posted on the symposium home page. Hit me below with any questions – and would LOVE to see you there!
Here in Michigan, spring is coming. Crocuses, snowdrops, and reticulata irises are in full bloom. Hepatica, forsythia, and daffodils will be coming on before long. Soon, garden centers and nurseries will be opening and gardeners driven mad by the long winter will rush out to buy every plant they can find with a flower on it. In the mad feed frenzy for flowers, we gardeners will sadly look over countless beautiful fall-flowering perennials and shrubs simply because they don’t happen to be doing their thing when we are shopping.
And that, my friend, is the tyranny of spring. We Northern gardeners all too often let our spring fever skew our gardens to all spring bloomers, totally ignoring and missing a vast array of gorgeous plants that give color and interest the rest of the year.
So, don’t give in. Try, for example, planting a bottle brush buckeye (Aseculus parviflora) a shrub which will thrill and delight with elegant white sprays of flowers in August when all the spring bloomers are looking tired and sad.
Or plant the lovely Hosta clausa which won’t impress with plain green leaves in the spring, but has a later summer flower display you won’t forget.
So this year, don’t give in to the siren song of spring. Add some late bloomers to the garden. You won’t regret it.
You know the word “rogue” as a noun and adjective, and probably from when Sarah Palin “went rogue” during her time as vice presidental candidate.
But you may not know that it also a verb. That’s the way I use it most often. I rogue plants and I complain — often — about seed producers not doing enough roguing.
To rogue means to weed out inferior or off-type plants. It is a critical part of producing and maintaining seed selections of plants. Whenever you are growing fields of plants for seed production, be it tomatoes or zinnias or corn, you get off types. Chance mutations, seedlings produced from errant grains of pollen from another variety, or just change of the diversity within the population. So one has to rogue — walk through the fields and pull out flowers that are the wrong color, corn plants that aren’t yielding enough, all the unexpected variants to keep the variety true to type.
The annoying thing is that a lot of seed producers cut corners — particularly, it seems, for annual flower seed — and don’t bother. The results can be very frustrating.
The worst are flowers in mixed colors. Maintaining a good mix of multiple colors requires careful roguing to ensure one color — due to greater vigor or just chance — doesn’t come to dominate. Lots of companies just don’t seem to bother.
Last year I bought a packet of Zinnia ‘State Fair’, an old, and wonderful seed strain, which was supposed to come in the full mix of zinnia flower colors.
I got pink. That’s all. Just pink. My whole row was pink. Not my favorite color of zinnia. Clearly the pink plants slowly came to dominate the fields of whoever is producing these seeds, and instead of roguing out some to bring the color mix back into balance, they just let them go rogue, and I got stuck with just one color.
The ‘State Fair’ zinnias were also supposed to be double, like this.
They weren’t. Single flowered forms will almost always come to dominate seed strains unless rogued out because they’re easier for insects to pollinate and thus tend to produce more seed. Clearly no one bothered, because every plant I sowed out gave me just a single row of showy petals.
I’ve had similar experiences with countless other varieties of seed annuals. The picture looks great on the packet, but sow them out and mostly what I get are rogues, not the variety I was after. The lack of roguing is a plague… bad enough that a friend in the horticulture industry once mentioned casually to me that, of course, cosmos varieties are only worth growing when they are first introduced. A few years without good roguing, and their desirable characteristics are mostly lost.
So more roguing please. I love growing big blowsy annual flowers from seed. I’m tired of them all going rogue.
As we get close to the time to start tomato, pepper, and other seedlings indoors, I thought I’d share this picture of my older sister’s seed starting setup from few years ago:
Two desk lamps with compact florescent bulbs. Not traditional, but worked great. Just a reminder that you can get creative when it comes to lighting for seedlings, using whatever fixtures and layout works for your space. The only rules are to use florescent or LED bulbs, not those old fashioned incandescent bulbs which have poor light for plants, and err on the side of more light rather than less to make sure you get compact, healthy plants that will transition to the sunny outside world without drama.
Ornamental onions are hot patooties. From big, bold, purple globes to small pink half-moons, there is no end to ornamental onion-y goodness out there with 30+ species and cultivars in the trade. There’s no substitute for ornamental onions in regards to architectural drama – the perfect geometric foil to wispy grasses, floral spikes, and umpteen daisy-thingies. The seed heads from the sturdier species will persist and add interest to autumn and winter perennialscapes (not sure if that’s a word).
All are members of the Allium genus, just like those onions sprouting in your kitchen counter veg basket – hence the deer- and small mammal- resistance factor. However…there are some issues.
Can be short-lived. I have first-hand experience with this – plant, enjoy for a year or two, then…where did they go?
Bloom time is rather vaguely defined. Most catalogs list “early summer” or “late spring” for most cultivars. But if you want continuous purple orbs, what’s the order of bloom?
Can be expensive. Bulbs for some of the mammoth “softball” sizes will set you back $5-$7 each (the bulbs themselves are huge). This is of particular concern due to the first item.
Foliage failure. For some of the largest species and cultivars, the foliage starts to die back around (or even before) bloom time. Not a lot of time to put the necessary energy back into that big honkin’ bulb.
We already have a multi-year lily perennialization trial going in conjunction with Cornell and some other institutions. I thought I might try the same thing with Allium.
Unfortunately, I had this bright idea in November – well into the bulb-ordering season. I tried to compile as complete an inventory as I could, ordering from several vendors. Ended up with 28 species and cultivars – as much as the space prepared (check out that nice soil!) could hold, at our urban horticulture center near campus (Virginia Tech is in Blacksburg, USDA Zone 6, about 2000′). We put five or seven bulbs (depending on size) in each plot, and replicated the whole thing three times.
We’ll take data over the next three years on time of emergence, bloom time and duration, foliage duration (have a nifty chlorophyll meter that can help quantify that), some growth measurements, and perennial tendencies (or not). My hope is to end up with a really specific chronology of bloom times plus life expectancy. Yes, this was just a patented Holly wild hair; luckily I had some general funds to cover it. But I do think our little onion project will be of interest to more than a few folks, whether professional landscape designers or home gardeners. I know I’m excited to see the results ($30 for five bulbs – yeek)!
At the top are Petunia integrifolia (purple) and Petunia axillaris (white) and below are an assortment of flowers from a population of F2 hybrids between the two. This cross is interesting because it is a recreation of the original hybrid that created modern hybrid petunia.
But more fun is a similar cross with the one hummingbird pollinated petunia, P. exserta! It is fun to see the ways the colors and flower forms recombine in new ways in the seedlings.
I don’t have anything profound to say about these pictures… just, hey, isn’t genetics cool?
Last year I was in England, and a snowdrop obsessive there (aka, a Galanthophile) showed me this cool trick, using mesh pots to keep her vast collection of different varieties organized.
She puts her bulbs in these pots (designed for use in hydroponic systems, I believe), and then sinks the entire pot down in the ground, so that the pot is invisible. The pot keeps the bulbs contained and easy to find so you can dig them up to divide or share even when dormant, and keeps different varieties growing next to each other from getting mixed up. But unlike a regular solid-sided pot, the open mesh allows roots and water to move freely so the bulbs grow just as easily and with as little care as if they were planted directly in the ground.
I’m not a snowdrop lover, they frankly bore me, but I have been getting more and more obsessed with bulbous corydalis, selections of C. solida and the amazing true blue Corydalis turtschaninovii. The tiny bulbs are impossible to find once they get dormant, and my collection is already beginning to get mixed up as the different varieties begin dividing and encroaching on each other… I’m going to start planting new editions in mesh pots to keep everything organized.