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The Cold Equation - Why Plants Die Over the Winter

The Cold Equation – Why Plants Die Over the Winter

By Jim Hole

By the time spring arrives, our gardens have endured a very long and arduous season. Months of sub-zero temperatures can take their toll on even the most stoic gardeners, but at least people spend most of their time on the warm side of the living-room window. Garden plants have little choice but to endure what winter throws their way. They must persevere or die.

Cooling Passions

What is it that allows a tulip bulb to survive extreme cold while a croton is damaged when temperatures drop to just a few degrees above freezing? The secret lies in water management. Plants have a love/hate relationship with water. During the growing season, plants are very enamoured with water, absorbing vast quantities of it to maintain vigour and encourage new growth. But during the winter, the love affair cools. Plants naturally retain some water within their cells. However, the water trapped in these cells is a recipe for disaster—when temperatures drop, it freezes and forms ice crystals. The expanding crystals burst cell walls, allowing the vital contents of the cell to leak out. The cell dies, and when this happens to enough cells, the plant perishes.

Coping Mechanisms

Plants that are native to areas with cold winters have several coping strategies to avoid the ice crystal problem:

  • One simple and obvious adaptation is the movement of the water out of the cells. Some plants transfer the moisture into the space between the cells rather than letting it lie within the cells and the cells do not burst.

  • Certain plants adapt by increasing the sugar or salt content within their cells. Water with higher levels of sugars or salts won’t freeze as readily as clear water —the higher the salt and sugar content, the greater the resistance to freezing. Ironically, plants may also suffer winter injury if their cells do not have enough water. Instead of freezing and bursting, these cells shrivel up and die from dehydration.

Running Hot and Cold

The water content issue isn’t the only factor involved in determining whether or not plants survive the winter. Sometimes, they are simply caught off guard. If temperatures drop rapidly following a warm spell, the plants do not have enough time to prepare for freezing temperatures.

Often, it is not low temperatures that kill plants, but rapid temperature fluctuations. It is much easier for a plant to adjust to gradual rather than brisk temperature changes and the ideal situation is for temperatures to cool slowly in the fall, remain moderately cold all winter, and then gradually warm in the spring. Of course, Mother Nature is rarely this benevolent. We’re all familiar with wildly fluctuating temperatures throughout fall and winter, and these conditions really test a plant’s hardiness.

Combating Winter’s Bite

There are ways to alleviate the winter weather woes:

  • CHOOSE HARDY PLANTS.

  • Take steps to protect your more vulnerable garden inhabitants. Mulches of peat moss and compost can stabilize root zone temperatures of perennials, while wind and sunscreen fabrics can be staked up to protect sensitive fruit trees.

  • Finally, give your plants a good soaking a couple of weeks prior to freeze-up. This will ensure that plants strike the right balance between too much and too little moisture. Ultimately, plant survival over the winter is part skill and part luck. Don’t be immobilized by the fear of losing a plant. Take a chance and plant a few of the more tender perennials and trees. A great deal of satisfaction in the garden comes when a gamble turns into a success.

The Scoop on Soil

The Scoop on Soil

A Beginner's Guide to Soil

Good soil is the foundation of a great garden. Without the right soil, whether in the garden or in containers, plants will wither. Sometimes the right soil is untouched clay loam; sometimes it's not soil at all, but a soilless mix. Tilling soil, adding organic matter, testing and adjusting the pH level—all of these actions give your plants the solid and nurturing earth they need to prosper.

A Simple Test

Reach down and gather up a handful of soil. Then, give it a squeeze. Does the soil hold together, or fall apart? If it does hold together, is it soft and springy or does it feel like a lump of clay?

What colour is it?If you have a nice, dark clump of earth that crumbles easily between your fingers, you're well on your way. Otherwise, your first step should be to improve your soil quality. Loam is the ultimate goal: a perfectly balanced blend of sand, silt, clay, and organic matter.

Soil's Job

Good soil must perform a number of functions. First, it should contain all the nutrients your
plants require. And good soil helps, rather than hinders, root absorption of plant nutrients. It
anchors plant roots firmly, but is loose and porous enough to allow them to grow and branch out.
Good soil retains moisture, but at the same time has adequate drainage to prevent waterlogged roots. Finally, good soil is neither too acidic nor too alkaline. All this is also true of soil in containers.

Amending the Soil

If you're not blessed with perfect soil from the start—and few of us are—you will need to amend the soil. That means adding plenty of organic matter: peat moss, well-rotted manure, or compost. Organic matter can be added to the soil anytime that the soil is warm enough to work, though the most convenient times tend to be in the early spring, before you've planted your gardens, or in the fall, after the growing season is over.

Amending the soil can take a lot of organic matter; generally, you need enough to cover your
beds to a thickness of 5-8 cm, or more if your soil is particularly dense (too much clay). Till in
the organic matter with a rake or rototiller, and you're on your way to a healthier garden!
Note that amending your soil isn't a one-time affair; since your garden uses the soil year after
year, it's only natural that the soil's quality will erode over time. Adding soil amendments once a year is an excellent way to keep your soil fertile.

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Podcast: Fall Pest Control - Jim Hole's Top 5 Tips

Are you wondering about controlling pests and insects in your yard but couldn't make it out to one of Jim's FREE talks? Well, you're in luck! Jim Hole has recorded a pest-control podcast on the Hole's Radio Network, available here.

In this episode of the Hole's Radio Network, Jim Hole chats with Brad Walker—the reluctant gardener—about the top 5 things everybody needs to know about pests and insects in the fall: where they go, how to keep them from taking over your garden, and when and how to apply your dormant spray kit (click here for details).

Play it below or download it by clicking here and, when you're done checking it out, please let us know what you think (by replying in the comments below). Also, let us know if you'd like to see more podcasts or video tutorials in the future.

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Podcast: Fall Bulbs - Jim Hole's Top 5 Tips

Are you wondering about planting fall bulbs but couldn't make it out to one of Jim's FREE talks? Well, you're in luck! Jim Hole has recorded a fall bulb podcast on the Hole's Radio Network, available here.

In this episode of the Hole's Radio Network, Jim Hole chats with Brad Walker—the reluctant gardener—about the top 5 things everybody needs to know about fall bulbs: from the right way to plant them, to the right time, and some secrets on what makes them bloom.

Play it below or download it by clicking here and, when you're done checking it out, please let us know what you think (by replying in the comments below). Also, let us know if you'd like to see more podcasts or video tutorials in the future.

Not All Grass Seed Is Created Equally By Jim Hole

Many people believe all lawn grasses are created equally. Nothing could be further from the truth.

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For example, many packages of lawn grass seeds come as a mixture of different species and varieties. Two types of grass seed that dominate these blends are perennial ryegrass and Kentucky bluegrass. Perennial ryegrass grows quickly, but is not particularly hardy; nor is it long lived on the prairies, but it germinates rapidly and emerges quickly from the soil. Kentucky bluegrass is the premium lawn grass for our region, but it is much slower to pop out of the soil.
 
Still, perennial ryegrass is good as a “nurse” grass to protect Kentucky bluegrass until it gets established. You just don’t want too much perennial ryegrass in a blend. Perennial ryegrass seeds are also much larger than Kentucky bluegrass seeds. In fact, a kilogram of perennial ryegrass contains about 500,000 seeds, whereas a kilogram of Kentucky bluegrass contains a whopping 3,000,000 seeds! Therefore, you can see that buying lawn seed strictly by weight is not a great strategy.
 
The bottom line is that a bit of perennial ryegrass is good for helping to protect your Kentucky bluegrass, but a lot of perennial ryegrass is a waste of money.
 
September is a great month for sowing lawn grass seeds, so choose your grass seed carefully! We recommend Manderley Seed. Find it here, at Hole's Greenhouses.

"Bulb Empowering"

When I hear the term "forcing" bulbs, I usually envision someone holding a flower bulb over a compost bin and yelling, "This is your last chance dammit! Bloom or I’m dropping you in."
 
But the term "bulb forcing" really hasn’t arisen out of any ill feelings towards bulbs. It’s used simply to describe a technique where one schedules flower bulbs to bloom within a particular time frame.
 
Amaryllis, Narcissus and Hyacinth are examples of forced bulbs that are commonly grown in our homes. At the greenhouses, we have a bunch that are quite content to sit dormant in boxes on our store shelves and wait patiently for customers to pot them for forcing indoors.
 
Each variety of forcing bulbs has its own "weeks to flower" schedule, based largely on its genetic make-up. Bulbs like Narcissus bloom quickly once potted-up, while Hyacinth and Amaryllis take a bit longer to display their gorgeous flowers.
 
Flowering times can be sped-up or slowed-down, somewhat, by manipulating temperatures. Cool temperatures delay flowering while warm temperatures reduce the time to flower.

Beyond their beauty, what I really like about forced bulbs is that they require so little care. The growers who have carefully nurtured them have already done most of the work. All I that I have to do is drop them into pots, add water, and enjoy.
 
Come to think of it, given that potting up a bulb is such a gentle and nurturing activity, coupled with our modern sensitivity to labeling things, perhaps its time to replace the harsh term "bulb forcing" with something like "bulb empowering".
 
Maybe "bulb emancipation" is an even better phrase, since we liberate the bulbs from their dry packages and transplant them into warm, moist, potting soil. Or perhaps consider "Manipulation of florogenesis of geophytes" if plant science is your thing.
 
Hmm… with some sober second thought, I think "bulb forcing" sounds just fine.

~Jim Hole
 

Marvelous Mums

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Fall mums are some of the most spectacular plants for our gardens. No other fall-flowering plant can match the colour of mums and they always arrive just when our gardens are looking a little brown and need a little brightening-up.
 
When it comes to fall mums there are roughly three categories based on flowering period: early, mid-season and late. Early varieties start blooming in August and into mid-September. Mid-season varieties bloom from late September and well into October, while the late varieties are for late October and November.
 
By now, anyone who purchased the early varieties (August-September bloomers) can see that they are well past their prime and have more dead blossoms than they do vibrant flowers. But, the mid-season types are just beginning to bloom. Mid-season types are, usually, bigger and more floriferous than their early season cousins and with cooler October temperatures, will last much longer than the early maturing varieties.
 
While garden mums won’t be killed by hard frosts, the blossoms can be damaged. What I like to do is leave the mums in their plastic pots and then just drop them into a slightly-larger, decorative pot so that they can be pulled out and placed in the garage should the night temperatures get really cold. Beyond giving them shelter when needed, mid-season mums just require some watering to keep them looking spectacular often until Halloween, and sometimes beyond.
 
If you are wondering about the late season mums keep in mind that, by November, we often get some pretty cold temperatures. Having said that, I have seen years where late season mums looked incredible well into the third week of November.

For me, the reward of seeing spectacular mums blooming in November outweighs the risk of damage from deep cold or heavy snowfalls!
 
Who knows, could this be the year of blooming garden mums in early December? I doubt it, but stranger things have happened!
 
Risk versus reward – everyone has their own formula.

~Jim Hole

Autumn Tomatoes

The end of the 2016 tomato season is rapidly approaching. That doesn’t mean that you need to run out to the garden and strip every last fruit of off each plant, but you do want to keep a close eye on the weather. If frost threatens, keep some "Cloud Cover" fabric handy and drape it over the tomatoes. The fabric will provide a few degrees of frost protection for the foliage and fruit.
 
When it comes time for the final harvest both ripe and green fruit can be gathered. Green tomatoes will ripen inside your home provided it has reached the "breaker" stage. The breaker stage is the point where the fruit has reached sufficient maturity so that it will change colour once indoors. Fruit that hasn’t reached the breaker stage–indicated by a deep green colour–will not mature inside regardless of what treatments you provide. Light green tomatoes have excellent flavour but the deep green ones are, typically, inedible.
 
One technique that a lot of people love, is to cut-off the entire tomato plant at ground level–fruit intact–and hang the plants upside down in a heated shed or garage. The tomato plants continue to send sugars to the fruit–if only for a short period of time–allowing some of the fruit on the "fringe" to ripen. The other good thing is that hung tomatoes are less inclined to rot while hanging because of better air movement.


~Jim Hole

FREE Pruning Workshop with Jim Hole!

Over the years, I would say that the main reason people don’t prune their trees and shrubs is due to a fear that pruning of the irreparable damage it cause.
 
But while it’s true, that a bad pruning job can lead to some serious tree and shrub problems, doing nothing can be even worse. That is why I’m putting on a fall pruning workshop.
 
Given that the spring pruning workshops were so popular, and the fact that a lot of pruning can be done in the fall, I’m offering an hour long pruning session on Sunday, September 21st for everyone who would like to know more about the principles of tree and shrub pruning and the equipment required to get the job done safely and effectively. The session is free and all that you need to do is sign-up on line and pop out.
 
And don’t forget to bring along your questions on anything from fall raspberry pruning to pruning huge American Elms.
 
And, no, there won’t be any lessons on how to climb a 20 metre tall Elm with a chainsaw in hand – that’s for certified arborists – but I will talk about all of the pruning jobs that you can comfortably tackle yourselves and the essential tools needed for safe and effective pruning.
 
Looking forward to seeing you on the 21st!


~Jim Hol

Growing Fall Bulbs In Pots

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When it comes fall planting, most people think of planting tulips into flowerbeds around the house or in the garden.
 
But here is something a bit different that you might want to try with your tulips this fall. Rather than planting your tulip bulbs into the ground, plant them into pots. I’ve done this for years because it is simple as can be, plus I have a blaze of colourful flowers long before anything else is transplanted outside.
 
Now, not everyone can put tulips into pots because one needs some free space and a cold storage area. But if you have garage or storage shed that is cold during winter (anything around the freezing mark but not down into the minus 20s!) and a bit of extra space, then you’re set. You’ll have tulips poking through the soil in March.
 

Here are the step by step instructions for very early spring tulips:

  • Choose a pot. I like bigger pots but smaller are just fine.
  • Add good quality potting soil to the pot. Garden soil is too heavy and dense, plus it often contains too many weed seeds.
  • Fill the pot to within about 15 cm of the top of the rim.
  • Place the tulip bulbs on the potting soil with the "pointy part up". Put lots of bulbs into the pot for a really good spring show. I like to plant the bulbs about 3cm apart.
  • Cover the bulbs completely with potting soil leaving a few centimeters of space below the rim so that the pot can be easily watered.
  • Water the pot thoroughly and then place it in a warm spot for at least 2 weeks to allow roots to develop. The rooted bulbs will not bloom, after rooting, until their "chilling requirement" has been met, which is equivalent to about a month or so of freezing to near freezing temperatures.
  • Once the bulbs have received their chilling requirement, they are ready to bloom. The trick at this point is to keep the tulips cold until you are ready to place them outside. If you warm the bulbs too early, the shoots will pop out of the potting soil and become floppy and die. I keep my tulips cold until about the 3rd week of March and then I place them on my deck and give them a good shot of water. If it does freeze outside even after the tulip shoots have emerged they won’t be harmed.


Usually, this pot planting technique allows me to enjoy tulips in early April - a good month before the regular garden tulips begin to bloom.
 
So if you have some extra cold space in your garage or cellar, give potted tulips a try. It really is a thrill to see tulips popping out of pots when there is still a foot of snow on the ground.

~Jim Hole

Planting Garlic and Irises in the Fall

Not everyone thinks of September as the time to plant things (most people are too busy harvesting their vegetable gardens), but for spring flowering bulbs, September and October are THE time to get things into the ground.

Irises are one of the fall bulbs that benefit from being planted first thing in September and we have some great new varieties available. Here are a few of our favourites on our shelves right now.

"Blue Suede Shoes" is a rich, gorgeously coloured, blue bearded iris. Blue flowers are hard to come by whether they are annuals or perennials, so to have a bulb that will come back in blue year-after-year is a pure delight.

As a bonus, this is a particularly fragrant iris and will rebloom as well. What more can you ask for? These blue suede shoes will leave you dancing with joy.

Another reblooming bearded iris, "Ancient Echoes" has some beautiful fiery colours. These flowers will add some striking contrast to your garden and will visually pop-out from quite a distance. Great for front yards if your goal is to get the neighborhood's attention!

Finally, a bit more of an elegant bearded iris, this "Bountiful Harvest" variety will also rebloom, making it ideal for cutflowers. Great for a more graceful style, consider this one if you like to have a classically beautiful garden.

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Fall is also a great time to plant garlic.

"Duganski" is a new variety for us this year, and it is fiery! Featuring purple stripes, it has a mellow aftertaste and is a great variety to plant if you like to cook with garlic a lot.

"German Hardneck" is another variety with a milder taste. If you like roasted garlic fresh out of the oven, this is THE garlic variety to use and plant as it roasts beautifully.

Finally, we also have "Elephant Garlic." While this is technically a member of the leek family, you'd never know it as it looks just like a very large garlic bulb and can be used in the same way. It is especially good raw because of its mild garlic taste... so if you're looking to make a pesto, tapenade, bruschetta, or salad, this is definitely a good variety to consider.

Growing Bulbs in Alberta and Picking the Right Bulbs for Your Garden

There is a myth that growing bulbs in Alberta is difficult.  

Well, I am Dutch, and I love bulbs, and I have successfully grown almost every type of bulb that I can lay my hands on, right here in Albertasometimes even growing tulips between my strawberries!

So growing bulbs in Alberta is definitely do-able and at Hole's, I get to choose from an amazing collection. My brother-in-law is the owner of one of the largest tulip growing businesses in the world and—while visiting Alberta from the Netherlands last year—he was so excited to find many of the world's rarest and most unique bulbs right here at Hole's Greenhouse.

But how to pick the right bulbs for your garden?

Well, I always have some early flowering crocuses planted near my front entrance, where I will see them every time I leave the house. As soon as the snow melts, the crocuses peep out of the ground with their delicate flowers, announcing the arrival of spring.

An added bonus is that crocusses will naturalize. That means that you only plant them once and they will come back every year with more.

Making it Pop

I find that bulbs have the biggest visual impact if you plant them in groups and in combination with another kind of bulb or with a perennial that flowers at the same time.

Power Combos

One of my favourite combinations for early colour is to plant the bright yellow dwarf narcissus along with the true blue star flowers of the Scillas. Both bulbs will naturalize and this combination works even in a shady garden.

Planted in between your hostas, they will put on a show before your hostas emerge and, later, the large leaves of the hostas will cover up the bulbs as the scillas and narcissus go dormant for the summer.

Timing is Key

Another trick is to find combinations of plants that flower at the same time. Sometimes that is just a matter of trial-and-error or sometimes it is just good luck.

One year I found a great combination, when I planted early purple tulips between my "Fire Cracker" moss phlox  (a ground cover smothered in vibrant fuchsia-pink flowers) and in between my Blue Fescue grass with its fine blue leaves.

Check the Package 

I always look on the package of the bulbs if they are early, mid, or late spring flowering. I find the early and mid-spring flowering bulbs especially interesting, because they flower at a time when not much else does.

Experiment!

This fall I'm going to try a combination of soft yellow "Peach Melba" tulips with a pink trim and flashes of green. In between the tulips, I'm then going to place some with light blue Puschkinias with clusters of star-like light blue flowers. It looks like a marvellous combination to me.  I am not sure if the timing will be right, but it is exciting to try.

I will let you know how it worked out in spring. The beautiful thing about bulbs is that, even if a combination doesn't work out, they're easy to move around.

 

BONUS: Book a landscaping design consultation with Maria Beers this fall and we will give you a FREE $25 gift certificate for our Glasshouse Bistro. 

Fall Gardening: Moving Perennials and Planting Trees in the Fall

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At this time of the year, I get asked everyday if this is still a good time to plant.

The fact is that for many plants fall it is actually THE BEST time to plant! It's also a great time to get deals on perennials, trees, and shrubs too!

Why is it the best time to plant? Well, with plants preparing for winter, there is no energy being used for new growth. Soon leaves will start to drop and the sap stream will stop. All the plant's energy will go to root development and the soil is still warm enough for plants to settle in.

That said, plants that you buy in a garden centre will probably be "root-bound" after growing in a pot for a whole season.  For this reason, it is really important to break up that rootball at planting time, to give the plant a chance to develop new roots. Massaging the rootball lightly will likely not be enough. If necessary, take a knife to loosen the roots and really roughen them up. Make sure you have watered the plant before you do this.

  • Fall is also a good time to plant, move, or split most perennials.You can still see what is growing where and it is easy to remember what was not working well.
  • Most perennials can be split and re-located in fall or spring, but for Peonies, Bearded Irises, and Lilies, fall is the very best time.
  • Tender perennials and grasses are better relocated in spring. Shrubs and most evergreens can be re-located till mid-October.
  • I would not plant or relocate cedars any later than the end of September. 
  • All other trees can be planted or transplanted for as long as the ground is soft.
  • If you have any hardy perennials or shrubs in a pot or planter that you would like to survive winter, then this is the time to plant them in the ground. In our harsh Alberta winters plants will almost never survive in a pot.

When transplanting, mix in some Sea Soil into the new hole that you've dug.Sea Soil is our best compost here at Hole’s. It is made from composted forest fibres and composted fish. It works well for just about any plant and I love the smell of it that reminds me of forest in fall.

Finally, remember to water your plants during fall and soak everything really well before the ground freezes, usually towards the end of October.

 
~Maria Beers
 

 

Maria is a landscape designer trained and educated in the Netherlands. She owned a landscape design business for 10 years before moving to Edmonton in 2005 and joining the Hole's team. Interested in booking a landscape consultation with Maria? Click here.

Frost Warning: What to Harvest, What to Cover, and What to Leave Alone

One of our customers woke up to this today! Did you get snow in your area?

One of our customers woke up to this today! Did you get snow in your area?

A frost warning is in effect and we've received a lot of phone calls from people asking about what can stay outside and what needs to come in. Here's our quick guide:

  • Apples: A light frost will not affect the apples and may even make them sweeter. Barring a severe September storm, leave your apples on the tree until they are ripe (mid- to late- September for most late bearing apples).
     
  • Beans and Peas: Will not tolerate frost. Harvest these guys and eat them up!
     
  • Beets, Carrots, Onions, Potatoes: Protected underground, these vegetables do fine in a light frost and their flavour may even improve with the cold. That said, harvest them before the ground freezes. 
     
  • Chard, Kale, and Cabbage: These plants should all survive a light frost. Cold temperatures will even intensify the colour and flavour of chard, and may sweeten cabbage.
     
  • Corn: Corn is frost sensitive. If your corn is ready, pick it now. If it is not yet ready to harvest, cross your fingers and hope for the best. A hard frost will reduce the shelf life of corn to 3 to 4 days.
     
  • Lettuce and Salad Greens: Cold will affect the look and texture of lettuce and salad greens, but they can survive a light frost. If you’d like, harvest the tops of the lettuce and see if they come back afterwards.
     
  • Tomatoes and Peppers: Harvest any ripe tomatoes and all peppers. Unripe tomatoes are bit more complicated. If you’re feeling cautious and would rather not deal with any stress, harvest them all now—ripe or not.

    If you’re feeling daring and if the forecast cooperates for the next day or two, you may be able to get away with bringing the tomato vines close to the house (preferably on the south side of the house) and covering them with some light bed sheets to protect them from the frost.

    However, if the forecast dips below -2°C, the tomatoes will probably end up covered in frost anyways even with these precautions. Keep an eye on your local temperature, and harvest the unripe tomatoes if necessary. Green tomatoes can be ripened inside on sheets of newspaper.
     
  • Pumpkins, Squash, Zucchini, Cucumbers: Cucumbers, zucchini, and summer varieties of pumpkin and squash should be harvested now, wiped dry, and cured in a hot, dry room for a few days to improve shelf life.

    Properly cured, they may store for a few weeks. Avoid storing these fruits on concrete or metal surfaces as it can cause them to rot.

    Thin skinned cucumbers will not store as well and should be eaten within a few days.

    Some pumpkins and squash are "winter varieties" and can store very well if properly cured. Harvest any mature “winter variety”  gourds before a frost (they will have a nice tough skin when mature) and do your best to protect the immature ones by covering them with a sheet. Immature gourds will not ripen off the vine or once the vine has died, so protecting them and hoping for the best is the best strategy. Be careful not to crush the vines.