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Allan designs and plants flowering gardens in Montreal, Zone 5 [USDA Zone 4] .

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Entries in Blue perennials (3)

Tuesday
Feb282012

I’ve Got the Camp-anula Glom-erata Blues!

Campanula glomerata, the species, from antonriver-conservation.org.ukCampanula glomerata, the species, planted over fifteen years ago, is gone. In a garden where neatness was paramount, it was an unwelcome visitor. It appeared messy in a new flowerbed that was barren and sparse, because all of the infant perennials were too tiny to fill up negative spaces. Furthermore, it self-seeded beyond my ability to control it. In addition, it sprawled all over, spread too quickly, bloomed for only two weeks, which is too short a time, didn’t look impressive, and didn’t project from far. Eventually, it was discarded when I found it wanting. I was happier gardener without it.

Today, my garden is filled with mature, stately perennials. There is less room for plants to self-seed. Large swaths of pastel colored flowers, that over time filled in the sparseness, are now better able to benefit from a  campanula's blue flowers. Furthermore, the hard-packed earth of yesteryears, that made maintenance a challenge, has been amended so that it is soft and workable. Plant spread is easier to control, seedlings are easier to dig out, and there are enough stately perennials in the bed to enhance lower growing plants.

I've begun to give Campanulas another chance; after all, they are blue - my favorite color. Two new varieties of Campanula glomerata attracted my attention. However, I am skeptical about the long term because I am not a diligent deadheader and that is what is required to keep the plants blooming throughout the summer.

Campanula glomerata Superba from Seemnemaailm.eeTwo years ago, I planted Campanula glomerata Dahurica in a client’s garden and I was happy with its performance.

Campanula glomerata Freya from Darwinperennials.com Last year, I planted Campanula glomerata Freya in my own garden and was more than pleased.

A one and two year span is too short a time for a gardener to report definitively about these plants. Therefore, all I can share is that they appear to be neat, they bloom for two or three months, and they make me very happy. The technical information about them, that follows, has been gleaned from the trade.

Campanula glomerata Superba from Robsplants.comCampanula glomerata dahurica 'Superba' has bell shaped flowers that are purple-blue with a glistening almost metallic sheen; they are borne in clusters atop stalks twenty inches tall above the basal foliage. Its thick, low growing and spreading clump should be dug up for division every third or fourth year. Promising to bloom from May to July, if spent flowers are deadheaded and foliage trimmed, the leaves will usually induce a second flush of flowers and the plant will be less likely to reseed vigorously. This sun-loving perennial will be long-lived only if it receives regular irrigation, as it is not drought hardy.

Campanula glomerata Freya from Whiteflowerfarms.comCampanula glomerata Freya is shorter than Dahurica; it grows only sixteen inches tall. However, blooms make up about two thirds of its height. Instead of bells, full clusters of small star-shaped lilac-purple flowers are borne almost all the way up the stems. Unlike other glomeratas, this variety is more floriferous. Like other glomeratas, it requires dividing every three to four years and spent flowers must be deadheaded. It is sturdy, non-invasive, and compact. While this perennial may be planted in full sun or part shade, it grows taller in the shade. At this time, there is no consensus on how long Freya will bloom. Some promise that itwill flower continuously from May to August, some say May to July, and others report May and June. Mine need another season before I can report accurately on this subject.

Wednesday
Dec162009

Aconitum: Toxic Perennial if Taken Internally

Image courtesy of Van Hoorn Nurseries.Aconitum is one of several impressive blue perennials used as background plants in English style gardens. The tall pure blue varieties make nearby pink flowers so vivid-looking that I needed to include Aconitum in my own garden. However, my eagerness for them ebbed when I found these plants at the nursery with a cautionary sign hanging over them that read: this plant is poisonous. Naturally, I chose not to buy. There have always been children playing in or near my flowerbeds. I did not want to deliberately create a scenario that might endanger them.

This stately perennial, also known as Monkshood, is one of the most poisonous of plants. Since ancient times, people have known that it is toxic and have used it as a weapon by coating their spear and arrow heads with its strong poison in order to kill wild animals. Some gardeners believe that this popular garden plant has such a distinctive and unpleasant taste that cases of accidental poisoning are rare, though known. However, all parts of the plant are toxic if eaten and its roots may be fatally mistaken for edible crops if left lying around. Even the abraded skin of a gardener can absorb a dangerous dose of its poison.

Image courtesy of Glenlea GreenhousesSome brave gardeners feel that handling the plant itself is not a problem and there is no reason not to grow it. I argue that if Aconitum were to be planted in ample-sized flowerbeds, such as those on large estates, one might not be so anxious about accidental poisoning. However, in tight urban flowerbeds, where gardeners often collide with their flowers, the possibility of a fatal accident is real.

Here are some of the symptoms of Aconitum poisoning: Burning of lips and mouth, numbness of throat, intense vomiting and diarrhea, muscular weakness and spasms, weak pulse, paralysis of the respiratory system and convulsions. Did you ever expect to read something as gruesome as this in a gardening blog?

Nevertheless, if a reader is determined to grow Aconitum, here is what one needs to know: This tall plant grows stalks that are so strong they do not need staking. There are many varieties of Aconitum, ranging in heights of 18 to 48 inches tall. The color palette includes white, pink and blue. The tall blue varieties are the most desirable because of the purity and intensity of their color. This perennial will grow in full sun or light shade but flowers get floppy with reduced sunlight. Aconitum performs best with a minimum of six hours of full sun every day. This plant blooms in late summer to early fall and is happiest in moist, fertile soil.

As soon as the first flowering flush is over, cut the bloom stalks to the ground to prevent seed development. This will encourage re-blooming later in the summer. Always wear gloves, long sleeved tops and long pants when gardening near this plant. Avoid placing Aconitum close to vegetable gardens or children’s play areas. Depending on the variety selected, this plant will grow in zones 2 to 8. I cannot suggest specific cultivars because I do not grow this species. As breathtaking as this perennial may be, the sounds of children playing touches me deeper.

Tuesday
Sep152009

Blue Perennials

Imagine how dull this perennial flower bed might have appeared without the blue flowers. This image was posted on line by Rsc Hydroseeding & Landscape Construction Co. Click on the image to visit their site.Blue flowers and foliage make an invaluable contribution to the perennial garden.  Blue makes every other color in the garden look better. In my review of the book “The Passionate Gardener”, I quoted the authors when they praised the color blue:-

 “Blue is an amazing color, seemingly effective with every other hue. It’s elegant with white, pale pink and cream. It shimmers with silver and chartreuse leaves. It glows with fiery orange or scarlet and smolders with maroon and blood red.”

 Below is a list of reasonably tame blue plants that work well in a perennial garden. Two that I have omitted, Baptisia and Brunnera, do not make a substantial color contribution. Aconitum, which is beautiful in blue, is also omitted because nurseries warn that it is poisonous to the touch. Myosotis is excluded because its vigorous self seeding habit makes it an invasive weed.

 Agapanthus, Agastache, Allium caeruleum, Aubretia cascade blue, Camassia, Clematis Elsa Spath and others, Catanache caerulea, Caryopteris, Campanula Blue Clips, Campanula porscharskiana, Delphinium, Festuca Glauca, Gentiana makinoi, Hosta Blue Jay, Iris Germanica, Iris Siberica, Iris Pumilla, Lobelia speciosa, Lavandula, Nepata, Perovskia, Penstemon strictus, Phlox subulata blue, Platycodon, Polemonium, Primula denticulate blue, Scabiosa Butterfly Blue, Salvia, Tradescantia zwanenburg blue, Veronica.