Fascinating Foliage

I don’t know about you, but when it’s cold out, I tend to pull in on myself—shoulders go up, chin comes down—it’s as if I’m trying to make myself smaller in order to  stay warmer. I thought of that recently as I’ve been observing the fascinating foliage on the P.J.M. rhododendron near my front door.

As the season changes, the rhododendron has been telling me how cold it is outside each morning. On chilly days — say in the teens or 20s — the leaves of the rhododendron are turned down and rolled in, sort of like a tube. If the weather is warmer—high 30s or 40s—the foliage is in its usual flat shape.

It was 18 degrees the morning I took this picture.

Rhododendrons are broad-leaf evergreens. Unlike deciduous shrubs, they do not lose their leaves over the winter. The buds for next year’s flowers and the leaves hold on through most of the winter. According to the University of Minnesota, the curling action is a way to hold onto water during the dry, cold parts of the year.  Sometimes curling is caused by disease, but that often happens during the growing season and this rhodie looked fine all summer long.

Rhododendron at 25 degrees

We’ve had a wet fall and this is a long-established shrub, so I don’t think it is struggling for water either. It’s perhaps just upset about the suddenly cold weather we’ve had! Are the leaves on your rhododendrons curling too?

Rhododendron at 40 degrees

Are We in for a Real Winter?

As I write this, it is Nov. 10 and the temperature outside is about 15 degrees. That’s cold, man! Even for Minnesota in late fall. The rather sudden drop in temperatures over the past couple of weeks has many gardeners wondering if we are in for a “real winter,” meaning one with lots of cold and snow.

The last time we had a significantly cold and nasty winter was 2014, when Minnesota schools were canceled for five days because of vicious wind chills. In 2016, I experienced the earliest first bloom in my Northfield garden ever with a bloom on March 13. That was also the longest growing season on record and we did not even have a frost in the Twin Cities until Nov. 7.

The National Weather Service has predicted the possibility of a weak La Nina system affecting weather here, which indicates it will probably be cold and wetter than normal. What does this mean for gardeners?

On Oct. 27, my alley garden was blanketed in snow, including the still blooming ‘Heavenly Blue’ morning glory.

If you still have fall garden work, get it done! I still have a few garden chores to do, including adding shredded leaves to my beds and cleaning out a few pots of annuals that I have not gotten to yet. It looks like this coming week will have a few slightly warmer temperatures and I plan to get out there ASAP to finishing things up.

Why I don’t spray—nasty Japanese beetles (top) and helpful bees coexist.

Fewer bugs??? Well, that’s the hope when we have a cold winter—that it will be cold enough to zap the Japanese beetles and other invaders that spend winter in the soil. Experts say that how much of the population of pest insects are killed by cold weather depends on 1) how cold it is and for how long; and 2) how much snow cover we have and when we get it—cold weather without snow cover is more likely to kill grubs nesting in soil. This article notes, however, that cold, dry winters also kill beneficial insects and, sadly, that Japanese beetle grubs can go very deep in the soil. Sigh.

More plant losses? Well, maybe, maybe not. We had a lot of rain this fall, particularly in October, which means plants are well-hydrated going into the winter season. With this early freeze, you could mulch around tender plants to make sure they don’t heave out of the ground during the inevitable thaw-freeze cycles. But, if we get some decent snow in December, we may just be in for a long, long winter.

Time to make some tea and get out a book!

 

 

 

October Surprises in the Garden

Fall may be the most pleasant garden season in Minnesota. Our springs are usually short and unpredictable. Summers can be cool and rainy or more often hot and humid—sometimes both. In fall, the mosquitoes are down, the humidity is usually not bad and it’s very rarely hot.

That’s why I’ve always planted a lot of fall-blooming perennials. This year, I have two perennials that are surprising me with how pretty they are — and an annual that took it’s time blooming but is now really putting on a show in my back alley.

The perennials are both natives to Minnesota, purchased from Prairie Moon Nursery as plugs last spring. This is the first time I’ve gotten so many blooms from plugs, which is likely because the number of weedy plants in my new garden is like, zero, where there were thousands of them surrounding my previous garden.  On to the surprises…

Clouds of blooms in late summer and fall on false aster

False aster (Boltonia asteroides): Truth in advertising, these look a tad weedy until they start blooming, and according to the Minnesota Wildflowers website, they can be aggressive. I’ve put them near my back fence, facing the alley, and they are in really rotten soil, so I’m hoping that will contain them. Now for the good part — the blooms! They are big, a bright white and yellow cloud of daisies. The plants usually start blooming in August, but mine did not bloom at all until mid-September, which may be related to the location.

It’s a pollinator magnet, too.
The bloom shape of wild quinine is airy.

Wild quinine (Parthineum integrifolia): I’ve heard several folks who are experts on native plants recommend wild quinine as easy care and attractive to people and pollinators, so I decided to give it a try in the new garden. The blooms come in August, but look pretty for a long time. They are often compared to yarrow because the blooms have a flat, sort of bubbly appearance. The foliage is large and a bit rough, so these will be moved this fall to the back of the border they are in.

The blooms of ‘Heavenly Blue’ morning glory really are blue but they change color over time.

‘Heavenly Blue’ morning glory: Like a lot of gardeners, I planted Grandpa Ott’s morning glory once and regretted it for years. (So did my poor neighbors, who ended up with a thick patch of it!) But I really wanted some screening between our patio and the alley and decided to grow ‘Heavenly Blue’ there. The plant took awhile to get started, but eventually it crawled up the trellis I gave it and took off in both directions along the fence. Starting about Sept. 20, it began to bloom, really bloom. That’s late for morning glories, but the pale blue blooms, which then turn kind of purplish and white as they fade are worth the wait.

Neighbors? What neighbors? Between the bean arch and the morning glories, I’ve got lots of cover.

Which plants are adding luster to your fall garden?

Minnesota’s Horticultural Heroes

On Sunday, I’ll be in Northfield talking about a few of Minnesota’s horticultural heroes who I encountered while working on my new book, The Northern Gardener: From Apples to Zinnias, 150 years of Garden Wisdom. The book will be released in about two months! But because I have a long association with the Friends and Foundation of the Northfield Public Library, my friends in the Friends asked if I would give a pre-publication talk for the Friends’ annual meeting. Happily! The talk follows the Friends’ annual meeting at 2 p.m., Sunday, Sept. 24, at the library.

The Northern Gardener book is a fun combination of history and how-to. It’s the kind of book I would have liked when I first started gardening, full of practical tips, solid information for northern gardeners, fun stories and an occasional eccentric character. It’s this last part that I’ll be focusing on in my talk with the Friends.

When early European settlers first came to Minnesota and other northern states, they were stunned by the weather—and by how limiting our cold climate was to what they could grow. They were particularly obsessed with fruit and their inability to grow the apples, cherries and other fruits that they enjoyed in the eastern part of the United States. This desire for apples is what led to the formation of the Minnesota State Horticultural Society and to more than 150 years of apple breeding, peony growing, tree hybridizing and a relentless drive to create hardier, more prolific and more beautiful plants.

One of these ladies was a Gold Star mother and state Victory Garden leader during World War II.

Minnesota’s horticultural heroes were an interesting lot, from the spiritualist who developed one of the state’s first hardy apples to the priest/professor who tested thousands of plants on the grounds of St. John’s Abbey to the Gold Star mother who organized Victory Gardens throughout Duluth and was the first woman president of the state horticultural society.

If you live in Northfield, please stop by to learn more about these horticultural heroes. Another note: the wonderful people at Content Bookstores will be taking pre-orders of the book at my talk.

 

 

Best of the New Annuals

Like a lot of garden writers, I get to try out newish plants, courtesy of plant wholesalers. For several years, I’ve gotten plants from Proven Winners and invariably there are indeed some winners among the plants.

This year, I grew two annuals from the sample plants that have grown really well, and definitely are among the “best of” plants for their categories.

He’s not visible in this shot, but there was a bee all over these guys when I took the photo.

Playin’ the Blues salvia — Part of a series called Rockin™, these deep purple-blue salvia have gotten zero attention from me, but have bloomed and bloomed and bloomed all summer long. Even in August, the foliage looks healthy and shiny and the flower spikes keep growing. I planted these in a bed that I’m planning to use for strawberries next year, so I basically threw whatever into it this year—the garden equivalent of a junk drawer. (That’s why there is a monster squash edging its way around the salvia.) The bed gets part-sun at best, and other than a little slow-release fertilizer in the planting hole, nothing else has been done to them.  Pest and disease free, the bees seem to love these plants.  The foliage looks better than any of my other annuals. They are winter hardy in USDA Zone 7 and higher, so for cold-climate gardeners these will have to be annuals.

Playin’ the Blues looking great in my “junk-drawer” garden bed.

 

Superbells® Over Easy™ is a Calibrachoa hybrid that does really well in containers. I planted these with some lilies, which have bloomed already, and some marigolds grown from seed. The white color with a dot of yellow at the center does remind you of over-easy eggs and the plants brighten up whatever else they are planted with. White is such a great color for adding contrast to the garden. Unlike some of my other petunias and calibrachoas, I did not need to give the Over Easy plants a mid-season trim in order to keep them blooming. The plants don’t get huge — staying under 12 inches tall, but they look neat and perfect flopped over the edge of a terra-cotta container.

Marigolds pair well with this yellow-centered calibrachoa, which is called Superbells® Over Easy™a new plant from Proven Winners.

What have been your best-performing annuals this season?

Disclaimer: I received free plants from Proven Winners to test for readers of this blog and Northern Gardener magazine. The opinions are my own and no other compensation was exchanged.

Reading Soil Test Results

Since I’m gardening in a new yard, I sent a couple of soil samples to the U of M Soil Testing Lab earlier this summer. Most horticulturists recommend a soil test as the first step in planning a garden because it helps you decide what additions, if any, you need to make to the soil.

For years, I did not have soil tests, but instead relied on the mantra: When in doubt, add compost. But I was concerned about the soil in my new garden, so I got the tests done.

A Solid C

The results came back within two weeks and, if my soil were getting a grade, it would be a solid C, maybe a C-.  While not completely surprising, the tests show I have a lot of work to do to build organic matter and soil fertility. I had two different samples tested because I have two distinctly different garden areas in the backyard: one that had been planted with turf and hostas previously and one that had been the site of an old garage. We scraped off some of the garage-area soil and added 2 inches of black dirt, but clearly that was not enough.

The better of my two soil test results is pictured above. This is for the turf/perennial area. It shows a coarse texture—more sandy than clay. The soil has a pH of 7.3, which is not terrible for Minnesota, and an organic matter percentage of 6.7 percent. My previous garden had a similar pH, but organic matter of over 10 percent. To be considered “organic” soil, a garden should have 19 percent or better organic matter. These garden beds will be getting a layer of leaves and compost over the winter and next spring to improve the soil fertility.

As with my previous garden, the phosphorus levels are sky-high. This garden has 51 parts per million of phosphorus, compared to a “very high” level of 25 ppm. My previous garden, however, had over 100 ppm of phosphorus. The potassium level is 76 ppm, a medium score, compared to more than 300 ppm on some soil I was sold for raised beds—which I think is too much.

The two key pieces of information from a soil test are the organic matter percentage and the fertilizer recommendations. The U suggested that any fertilizer I add to these beds have a ratio of 7-0-10—so no phosphorus, but some nitrogen and some potash.

Sandy, Clay or What?

The soil on the site of the former garage was also labeled as coarse by the U, which shocked me considering how difficult it has been to dig in. If the soil is wet, it actually makes a sucking sound when you pull a shovel of dirt out of it. It does have a lot of rocks, so I decided to do the low-tech test to find out if your soil is clay or sand.

This is the test where you put a bunch of soil in a container, shake it up with water and let it settle. Because of the relative weight of the different types of soil (sand, silt and clay), the soil will settle out in layers, with the heaviest layer (sand) on the bottom and the lightest layer (clay) on top. For a better explanation of how this works and how to use a soil chart, check out this fine video.

It took forever for all the sand and silt and clay to settle out of my jar. The photo above was taken 48 hours after I started the test. Most of the videos/pictures I’ve seen show clear water on top and clear layers. My jar has some layers, but there is still a lot of soil floating around in the water.  The soil did not fully settle out until about a week later.  My best guess on composition is it is 50 percent sand, 20 percent silt and 20 percent clay. According to the soil chart (below), this kind of soil is considered loam or clay loam, which should be decent garden soil.

Perhaps the problem isn’t the rocky (inorganic) part of the soil, but its complete lack of organic matter. According to the U, the organic matter level was an abysmal 2.7 percent. This is the reason I’m growing vegetables in raised beds.

But here’s the funny thing about this potentiall atrocious soil–stuff is growing in it! I planted some cosmos and they seem to love it. I put in five plants of ‘Blue Heaven’ little bluestem and they’re happy as can be, as is a ‘Little Henry’ sweet black-eyed Susan plant that I got at a garden writers event earlier this summer, some Russian sage and even allium bulbs. Not everything likes that soil, of course, and three honeyberry plants that I thought might do well there, up and died in just a few weeks. Very sad.

My plan is to buy additional native and prairie perennials for the areas around the raised beds, which will be good for attracting beneficial insects. I’ll also add leaves and compost, but getting this soil to the “organic” level is going to be the work of many years.

Have you had a soil test on your garden? How does your soil measure up?

411 on Cracked Tomatoes

I was out of town Wednesday night and came home to three inches of rain in the rain gauge and a handful of cracked tomatoes.  The two items are related.

Why Tomatoes Crack: To grow well and fruit profusely, tomatoes need even, consistent moisture. I water tomato plants during dry periods to encourage fruiting and healthy growth. But when Mother Nature dumps a bucket of moisture on the ground, the plant naturally takes it up and the fruits crack. Their skins can’t grow fast enough to take in the extra moisture. Cracking is most common with a heavy rain after a long dry spell, though this was not the case here because we have had an unusually rainy August. As typically happens, the fruits closest to ripeness cracked.  The cracks in the fruits provide an entry point for bacteria and fungi, and typically the fruit will rot quickly—in fact, I tossed one really rotten tomato before taking the picture.

Can you prevent cracking? You can’t prevent cracking from extreme storms, but you can prevent losing tomatoes due to cracking, by harvesting tomatoes most susceptible to cracking. Green or very unripe tomatoes are less likely to crack, so picking those that are ripe or nearly so before a big storm is a good way to prevent cracking. Since I was away during the last storm, I picked a lot of ripe or nearly ripe fruit right after I got home. You can prevent cracking if the problem is dryness by watering regularly.  You also can reduce cracking by growing tomatoes in raised beds, which drain more thoroughly than in-ground gardens, and by applying a layer of compost or other mulch to keep soil evenly moist in dry periods.

Are there tomatoes that don’t crack? Yes, there are some varieties that resist cracking. (Those that crack the most tend to be heirloom varieties and large tomatoes.) You can find a long list here of crack-resistant varieties. Popular varieties that crack less include Arkansas Traveler, Celebrity, Big Boy, Big Beef, Summer Sweet, Sungold and Yellow Pear. If cracking tends to be a problem with your tomatoes, you may want to choose a crack-resistant type.

What about calcium and cracking? Calcium helps tomatoes regulate their intake of moisture, and a shortage of calcium in the soil is also linked to blossom end rot, another really discouraging tomato problem. Some gardeners add crushed eggshells to the planting hole, antacid tablets or a commercial calcium to increase the calcium available to plants. Consider a soil test before you heavily supplement the soil.

We have more rain in the forecast for the next couple of days, so I will be harvesting more tomatoes today. How are your tomatoes doing during this rainy period?