Rhododendron and
Azalea News

Gardens

Visit to Dawyck Botanic Garden, Scotland

May 2008 will be coming soon and many ARS members are planning to participate in the Silver Jubilee in Edinburgh, Royal Botanic Garden.  This event is described more fully in the People and Events section.

Fiona Campbell of the Scottish Chapter has written an article that will certainly whet your appetite to go and celebrate.  Listen to what Fiona has to say. 

My husband, Willie Campbell and I have visited the Botanic Garden at Dawyck...which is near Peebles in the Scottish Borders...on several occasions over the years and have found the Arboretum a wonderful place for those interested in trees and shrubs...as well as rhododendrons.  It is part of the Royal Botanic Garden, Edinburgh, having been gifted to the nation in 1978 by Col. Balfour. Dawyck is truly one of the world’s finest arboreta. With conifers dating back to 1680.

I followed the David Douglas Trail and found a fascinating mix of mature trees and shrubs.  Many have come here from the plant hunting expeditions of the 19th Century...as well as the more recent one in the 1990s.

Near to the entrance is the azalea border and some rhododendrons, such as R. campanulatum and R. oreodoxa.  These beds are sheltered by huge oak, beech, and conifer trees, and the plants surrounded with bark mulch.  Further on R. bureavii with a mass of cinnamon brown new foliage.  Also of interest was the group of twelve or more R. roxieanum and R. roxieanum var. oreonastes all showing off their new foliage and their wonderful mounded habit of growth.  Other rhododendrons, whose new blue foliage stood out against the predominantly green background were R. oreotrephes and R. campanulatum ssp. aeruginosum.

The well-marked David Douglas Trail has many signs indicating all those "special trees" of note and other plants which were introduced by him commonly found in our gardens today.  There are many conifer giants to be seen, notably the Douglas firs, one specimen was multi-stemmed where the leading shoot had suffered from a grazing animal, or damage of some kind in its early days.  This was indeed a spectacular tree.  Noted an Arolla Pine, Pinus cembra, planted in 1870 was measured at over 48 m. in 2001 and is the tallest tree in the garden.  Near by is a Lawson Cypress planted in 1859 and 37.5 m+ tall.  There are many species of pine, fir, Western Hemlock, and Chamacyparis, all showing their different foliage colors, and formations.  These giant trees can be seem from a higher viewpoint on the Beech Walk...further down the Trail.

Fiona shares just a little of her joy about the gardens of Scotland.  John Hammond has been dedicated to making this ARS Celebration the best ever for several years now.  Do take a minute to review his invitation in People and Events.

Catnip...a great perennial plant

Norma Senn of the Victoria Chapter has some real pointers to direct our attention to a leading perennial...catnip.  Maybe some things she has to share will influence you to have a plant or two in your garden.

The Perennial Plant Association has named Walker's Low Catnip as the 2007 perennial plant of the year.  The variety takes its name from the Irish garden, Walker's Low, where it was first grown.  Patricia Taylor, the garden's owner, made the original plant selection in the 1970's and it was introduced to the horticultural trade in England in 1988.  Since then, it has become popular in home gardens, and is readily available throughout Europe and North America.

characteristics of catnip…

Like all catnips, Walker's Low has aromatic, gray-green leaves, and stalks of bluish/purple flowers.  The flower stalks can grow to almost a meter in height and are very attractive, both when grown in a massed planting, or when individual plants are mixed with other herbaceous perennials and the flowers are allowed to poke their way up among the leaves of other plants.  If deadheaded regularly, flowers will be borne periodically through the summer.

good companion for roses...

"Walker's Low, like other catnips, makes a particularly good companion plant for roses.  Plants are shorter than the flowers and they have an attractive mounded habit that makes them useful in mixed borders and herb gardens.  Like other members of the mint family, all catnip leaves are arranged in a distinctive opposite pattern along square stems.

how to grow...low maintenance...

Catnips are easy to grow if they are given well-drained soil and several hours of full sun per day.  They will tolerate partial shade...but flowering may be compromised.  As well, they prefer soils with a neutral pH...so if you garden in an area with acid soils, adding calcium carbonate or dolomitic lime to the soil at planting time is recommended.

Occasionally shearing plants back will keep them looking fresh throughout the summer.  Other than that, they are low maintenance plants with few problems.  Most catnips, including Walker's Low, are hardy into Zone 3.

origin

The majority of catnips grown in home gardens are thought to be of hybrid origin and belong to what is botanically referred to as the Faaseen group.  They probably originated from crosses between Nepeta nepetella x Nepeta racemosa.  To maintain desired traits, named varieties like Walker's Low need to be propagated vegetatively...either by dividing existing plants or started from cutting.  Watch for young plants in local garden centers in May.  Catnips can be grown from seed too...but seed-grown plants will be variable in habit.  Cuttings root easily, so once plants are established home gardeners can take cuttings if more plants are wanted.

catnip for your cats...

Of course, catnip is well-known for its effect on cats.  However, cats find some catnips more enticing than others...and anecdotal evidence suggests that Walker's Low is not particularly attractive.  So you don't need to be concerned that planting this particular variety will attract all the cats in the neighborhood.  If you do want to grow a treat for your own pet, then select another variety, or grow plants from seed.

In addition to some catnips being more enticing than others, not all cats are attracted to catnip.  The reaction is an inherited trait and about 30% of adult cats are completely unaffected.  Interestingly, until they are 3 to 4 months old, kittens are actually repulsed by catnip, and many cats are less interested in it as they age.  Larger members of the cat family like tigers, bobcats and cougars are also attracted to catnip...but again...not every animal within a species responds.

aroma causes euphoria...

It is catnip's aroma that causes euphoria...and the active ingredient is a volatile, aromatic chemical called nepetalactne that is released when plant leaves are bruised or crushed.  There is more nepetalactone in fresh catnip than in the dried product.  Cats "under the influence" will roll, leap about, possibly meow or growl, and in general, just act silly for several minutes.  Then, the stimulus loses its effectiveness and it takes a couple of hours before the cat will respond to the leaves again.  As long as a cat is healthy, catnip does not harm the animal in any way.  However, I have read some warning that old, obese cats or diabetic cats probably should not be exposed to catnip because it may cause an accelerated heart rate.  According to some sources, catnip was deliberately cultivated by the ancient Egyptians who recognized its effects on cats, and the catnip now found growing throughout Europe spread from the Middle-East.

used in herbal remedies, too...

While catnip is a stimulant for our pets, it has also been used in herbal remedies for people for centuries.  It is said that herbal infusions containing catnip leaves are helpful in curing colds, relieving headaches, and soothing nerves.  It was introduced to North America by early colonists and it quickly spread throughout much of eastern North America.  First Nations peoples soon recognized its usefulness, and like Europeans, valued it as a flavoring and medicinal plant.

an added plus...lots of insects

In addition to being attractive to cats...bees and butterflies adore catnip flowers...and you will find your plants humming with insects when they are in bloom.  Deer and rabbits, however, are not fans...so catnip is a good garden choice where deer and rabbit resistant plants are needed.

Consider again...some catnip...in your garden this year and the one following it...and another year!

Companion Plants: Calluna

Colleen Forster of the Fraser South Chapter writes...

If I hear just one more person say, "Oh, I don't like summer heathers...they always look so ratty,"; am going to scream!  Never have I seen a more mistakenly maligned plant in my life.  Properly grown...they are a glorious delight...and I defy anyone who has seen them, mile after mile on the moors of England in all their wild splendor, to disagree.

The singular species, C. vulgaris, inhabits large portions of Europe and northern Africa, from Siberia to Morocco, in vast tracts of open land and hillsides.  The predominant flower color is purple...but it sports out in pink, red, and white.  For well over 100 years, avid plants men have made over 500 selections of form, bloom, and foliage variations...and some of them are real eye-poppers!

Now, if you are one of those guilty of such slander in the past, I am about to show you the error of your ways.

guidelines for success...

• Site selection is probably the most important factor. These are ericaceous plants...in the same family as rhodos...and like them, we should take our lessons from Mother Nature.

• Full sun is an absolute must...and some slope to the ground is very beneficial.

• Soil should drain well...but retain some moisture, especially in summer during bloom time...anywhere from July to November depending on cultivars.

• An acid, humus-rich soil with no manures or strong fertilizers is necessary...a lean media keeps the growth compact.

• If you cannot engineer even a bit of a slope, then be sure that the soil is deep and loose.

• And then...prepare to PRUNE!

Ok, ok, and ok!  I know no busy band of elves prunes on the moors, but truth be told, if you took aside only one or two of those million of plants, they probably would be ratty...but there’s safety in numbers and distance.  We do not have that advantage in our gardens...so get out the hedge clippers.

March is a good time to do this...trim just to the bottom of last year's flower spikes to make a somewhat mounded shape.  Now, was that so hard?  Once a year is all it takes, and a spring pruning still lets you enjoy all that wonderful winter foliage on the colored forms.

choices...choices...world to choose from...

Choosing varieties for your garden will be by personal preference.  With that many to pick from, it is like roses or rhodos...grow the ones you like to look at.  I can only give guidelines of the forms that are available.  The flowers can be single...or double...on long or short spikes.

I have taken full open spikes of 'Peter Sparkes' and 'H.E. Beale' and hung them to dry, and they make wonderful bouquets...unfortunately, not too durable...but so easy you can do new ones every year.  Colors range from white and pale pink to bright pink, crimson, and purple.  There are varieties like 'Marleen' that seem to bloom forever since the blossoms don't ever actually open, just show outer color.

The foliage on some is so spectacular that even if they didn't bloom, no one would notice.  Red-gold ones like 'Firefly', 'Blazeaway', 'Boskoop', and 'Sir John Charrington' are bright all year round.  Silver ones like 'Jan Dekker', 'Silver Knight', and 'Grey Carpet' will gleam against dark backgrounds.

Some...like 'Spring Torch' and 'Spring Cream', have colored foliage on new growth only...almost like an early bloom...and then the proper flowers come later.  Very dwarf ones can be used in troughs or rockeries, as 'Foxii Nana', 'Dainty Bess', 'Humpty Dumpty' and 'J. H. Hamilton'.

The list is endless...but this should give you an idea of the lovely ones there are to choose from.  Visit gardens and plant centers in summer when they are in bloom.  I only wish I had more room in my garden to have an entire bank devoted to them...in drifts of all year color.

Happy planting!

A good thought to ponder on...

And he is happiest who hath power
To gather wisdom from a flower.

-- William Wordsworth