Category: Gardening

Centaurea macrocephala

knapweed_3Also known as Lemon Fluff, Golden Thistle, Bighead Knapweed, and Armenian Basket Flower is now on the prohibited list and must be destroyed by anyone growing it. If you have this plant in your garden, please do not share it or let it go to seed, please remove it now.

This perennial has large showy, single yellow flowers and large, broad, rough, hairy, lance-shaped leaves with pointed tips. Its roots are woody. Centaurea macrocephala grows to 1.5 metres tall and is a prolific invader spread by seed. Easy to spot and identify when blooming.

Alternatives include the Centaurea dealbata, a pink/purple blooming knapweed also called Persian Thistle or Persian Cornflower, and any one of several varieties of yellow blooming Heliopsis or false sunflower.

More from the Alberta Invasive Species Council…

From bud to seed:


(All photos: Marie Wenger, 2011)


Lucy ChangLucy Chang

The Traveling Trowel

Photos by Richard Knapton

There is surely no sight more evocative of spring than a show of tulips, so here is a quick visual tour of tulips in the landscape – in the ground, in containers and raised beds. I hope you will be inspired by the creative ways (block planting in squares, circular patterns, drifts, linear grouping, informal clumps, monochromatic scheme, etc.) that tulips are displayed. The colourful offerings of these bulbs seem all the more enchanting as we zone 3 gardeners break out of our long cold icy-white hibernation!

Keukenhof Gardens – Holland

[Note: in the following galleries, hover over the photo for informative captions and click for a larger image.]

In – ground mass displays

Container Displays

Watch for more photos from Lucy’s tulip-mania collection coming in the fall of 2014. And see also her Tulip Tips.

Lucy Chang is a past EHS President and avid gardener. She and husband Richard Knapton own Eagle-Eye Tours and offer birding and garden tours in various parts of the world.

Tulip Tips – from our zone 3 garden observations

Lucy Chang

Peony flowered tulips

Peony flowered tulips

The Travelling Trowel

The tulips in the gardens I’ve visited (see Tulip-Mania) are planted every fall – the only way to have a reliable floral display every season. Spent bulbs are replaced with healthy fresh bulbs selected for size and uniformity, colour theme of the season and/or specific attributes of the cultivars (striped, fringed or flamed petals).

It helps to know the types of tulips that you are planting: species or hybrids; early, mid-season or late bloomers.

In their natural habitat (temperate Europe, Asia and the Middle East, from gravelly ground at sea level to steppes and alpine conditions, usually in open environments) species tulips bloom in the spring, rebuild energy in the bulbs through the leaves before they turn brown and drop off, and then the bulbs rest underground in dry summer conditions. The bulbs go dormant in winter and wake up ready to bloom in spring.  Species tulips are perennial performers (e.g. Tulipa tarda, T. fosteriana, T. kaufmanniana). Hybrids or cultivars that retain major characteristics of the species parent can be relied on to return and bloom every year. They are generally early bloomers. Some modern hybrids that are far removed from species tulips are one-time bloomers. Some others peter out after the second season.

T. 'Vincent van Gogh'

T. ‘Vincent van Gogh’

In our short growing condition with unpredictable frosts, tulip bulbs do better planted much earlier in the fall than instructed in the package. The bulbs need to develop roots in cool moist soil condition before the ground turns cold and dry, and the soil become less friable. The roots will pick up moisture and nutrients and trigger bud formation. Then in response to falling temperature, the bulbs will prepare for dormancy. If they do not develop proper dormancy, the bulbs will die in our extreme winter temperature or rot in cold soggy ground.

Due to the influence of climate change, winter may swing straight into summer in terms of temperature, and shrubs and trees will leaf out earlier than expected. This timing may impact any late blooming tulips that are planted in the shadow of the shrubs or trees.

Repeat freezing and thawing is hard on bulb dormancy. If fooled into breaking dormancy too early, the next freeze may kill the bulbs. Some tulip experts advised planting tulips deeper than recommended in the package so that mid-winter thawing will not affect dormancy.

Plant tulips in well-draining soil as rapid snow melt following a winter of extreme snow fall may produce prolong waterlogged condition that could be detrimental to the bulbs.

Tulips are usually planted in perennial beds that are treated with regular watering and fertilizing throughout the growing season. This encourages the tulip bulbs to fore go resting and develop baby bulbs that may not mature to blooming stage for several growing seasons. The mother bulbs become smaller from depleted energy. This may explain (depending on the types of tulips that you are planting) why tulip flowers become smaller or fail to bloom in successive seasons. Lifting the bulbs after the leaves have faded and allowing them to rest in a shady dry place before replanting in the fall is one way to retain the flowering vigour of the mother bulbs.

Tulipa greigii cultivar

Tulipa greigii cultivar

It is important to deadhead the flower once it has faded so that the plant’s energy is not directed to nurturing the seeds, but recharging the underground bulb. Allow the leaves to fade naturally and go brown and limp. The green leaves are necessary to manufacture food for the bulb.

Last but not least, a very good reason for no-show tulips could simply be your local common wildlife. Mice, voles, raccoons or squirrels all could feast on the bulbs. Rabbits have nibbled emerging tulip shoots to soil level in my garden. With that development cycle broken, those particular bulbs never performed as well again.

I hope you have enjoyed this electronic “tip-toeing through the tulips” with me. Until the next stop, have a great spring!

Lucy Chang is a past EHS President and avid gardener. She and husband Richard Knapton own Eagle-Eye Tours and offer birding and garden tours in various parts of the world.

The Prairie Short Season Yard

By Lyndon Penner


Everything you need to know for a quick and beautiful yard on the Canadian prairies

Creating and maintaining the perfect yard on the prairies isn’t as hard as you might think, but the short growing season doesn’t give you much time to transform your winter-weary yard into a glorious garden. To help Western Canadian homeowners get the jump on the short season, popular gardening expert Lyndon Penner has created the essential guide to a quick and beautiful yard on the Canadian prairies.

With gardening smarts, style and wit, Lyndon covers everything both novice and expert gardeners need to know, along with tips you won’t find anywhere else. Contains more than 200 beautiful, colour photos.

  • Quickly find what you need to know about climate zones, soil, colour, texture, and shade.
  • Understand your yard’s potential.
  • Pick the best bulbs, perennials, trees and shrubs for your yard.
  • Deal with insects and plant diseases in environmentally friendly ways.
  • Shop smarter at garden centres.
  • Attract animals you want to your garden, and keep away the ones you don’t.

 About the Author

Lyndon Penner, gardening rock star, has been getting dirt under his fingernails since the age of three. He’s never forgotten the thrill of growing his first flowers from seed. A landscape designer and horticultural consultant, Lyndon is a gardening columnist on CBC Radio in Alberta and Saskatchewan. He appears frequently as a guest speaker at universities and colleges in Western Canada. Lyndon lives in Calgary.

The Prairie Short Season Garden, Lyndon Penner, published by Brush Education Inc. 2014.


The Garden in Winter: Plant for beauty and interest in the quiet season

As we complete the Winterscapes program for EHS in March 2014, I thought it would be useful to seek references that would help us better understand winter gardens.  I retrieved from the Edmonton Public Library the book The Garden in Winter by Suzanne Bales.

I found this book to be jammed full of photos of winterized gardens. After all, gardens in winter are very visual and appealing, right?  Okay maybe not so much when it is bitterly cold, but they can make you stop for a moment to admire them. Something is bound to catch your eye—the way the snow and ice contours the landscape, birds hopping around with boundless energy, the effect of sun and shade on the garden portrait….

Catch some of the chapter titles: The Wonders of a Winter Garden, The Glory of Trees and the Beauty of Bark, Colorful Conifers and Broadleaf Evergreens, and so on.  This book helps us find the beauty of the winter landscape.

While this book and the photos are not focused on the prairie landscape, they do provide ideas for winter garden design.  As the subtitle suggests: Plant for beauty and interest in the quiet season.

The Garden in Winter: Plant for beauty and interest in the quiet season, Suzanne Bales, Holtzbrinck Publishers 2007, distributed by Rodale. Available at the Edmonton Public Library.

Reviewed by Neil Lang, EHS Front Yards in Bloom Coordinator