Archive | Rhododendron

Rhododendron Birds

Widgeon

Rhododendron Widgeon was been beaten to a great post by Jo Hanslip on insane journal

‘The Glendoick Bird Hybrids

The Bird series of dwarf rhododendrons were developed at Glendoick Gardens, in Scotland, and are classified as Dwarf Lepidote Hybrids.

The great plant hunters Ludlow and Sherriff returned to Britain in the 1950s. George Sherriff and his wife started a garden only 50km away from Glendoick and they became great friends of the Coxes. On an early visit to their home, Ascreavie, Peter Cox spotted a dwarf yellow-flowered rhododendron species with enormous bowl-shaped flowers for the size of the plant which turned out to be … Rhododendron ludlowii.

The Sherriffs allowed Peter to take some pollen home, which he applied to R. chryseum …  In due course, the hybrid R. ‘Chikor’ was selected and named from this cross and … given an Award of Merit by the Royal Horticultural Society.

A chikor is a game bird and this started the theme of naming all dwarf lepidote hybrids after birds, another prime interest of Peter’s. From then on, several dwarf crosses were made every year with Kenneth Cox starting to make his own crosses in the early 1980s. There are now 30 Glendoick birds which are popular with gardeners and rhododendron collectors in many parts of the world.

BRAMBLING 90cm. New Glendoick hybrid with brightest pink flowers in multiple clusters in April. Fine dark foliage.
CHIFF CHAFF 60cm. Masses of creamy yellow flowers in early May. A neat bush with handsome dark foliage. One of the original bird hybrids, raised in the 1960s.
CHIKOR 30cm. Bright yellow flowers in May. The first Glendoick Bird hybrid. Compact twiggy growth. Needs cool roots & good drainage.
CRANE 75cm. Creamy-white flowers in April. Hardy, very free-flowering and easy to please. One of the best white dwarf hybrids. Continue Reading →

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Grewelthorpe Himalayan Garden Images

The Himalayan Garden at Grewlthorpe continues to mature and develop. It is great to see a wide range of trees allowed to grow their natural size without undue lopping or arbo work.
A new arboretum will open at the end of May 2017 and the next autumn season will be worth a special visit.

As ever the sculptures are excellently located and seem to breed in number every time I visit.

Rhododendrons are the key feature for me that makes return spring visits a must.

Landscape views from the many well located paths are set to delight.

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Pruning Deciduous Azalea and After Care

Azalea Mollis aka Rhododendron sinensis

This species of plants originate in central China. The closely related species R. molle japonicum come from Japan. Both these deciduous varieties are relatives of the popular Ghent and Knapp Hill hybrids.

They are one of our favourite flowering plants with bold, colourful, spring blooms that are not hidden by lime green leaves that appear around flowering time.

A North American variety R. calendulaceum is called the “Flame azalea” due its fiery orange colours and autumn leafs. R. luteum is not surprisingly yellow.

Pruning Azalea

  • Where possible avoid pruning but if needs must then wait until flowering has finished.
  • Water the shrub and keep it well watered through late spring until autumn.
  • Take out dead or damaged wood with sharp secateurs.
  • If reshaping or drastic pruning is needed expect to loose the flowing capacity for one or two seasons.
  • Thin water shoots from the base can be thinned in number to encourage the others.
  • Remove one older stalk to create light space and shape if you must.

Azalea

After Care

  • After care will help the plant recover from shock.
  • Apply an ericaceous acid plant fertiliserlike miracle-gro specially formulated for azaleas, rhododendrons, camellias, dogwoods and magnolias. Feed through summer.
  • Mulch around the base of the shrub.
  • Other acidifying feeds and treatments include vinegar, ammonium sulfate, iron sulfate or flowers of sulfur but take care as some may burn the shrubs.
  • Dress the top soil with peat or an ericaceous compost

Read more

Rhododendron Pink Pearl

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Himalayan Gardens in Yorkshire

In Yorkshire we are lucky to have several gardens designed using the theme of a Himalayan Garden. The Hut near Ripon at Grewlthorpe is   ‘The Himalayan Garden’ with all the plants you would expect in such a setting including

Rhododendrons both Hybrid and Species over 50 varieties
Evergreen and Deciduous Azaleas
Eucryphia varieties growing 10′ – 30′ as trees and large shrubs
Magnolias and Camellias
Cornus
Bamboo
Primulas and Meconopsis
Himalayan garden Grewelthorpe Meconopsis7
Visit between April and June for the best colour display.
Continue Reading →

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Rhododendrons and the Danger of Frost.

Frost damaged Rhododendron
My Rhododendrons were in full bloom when a late frost caught them quite badly.
Winter has been wet and mild but if the USA is anything to go by hard frosts may still be on the way so look after your early flowering Rhododendrons.

early-rhododendron

Although Rhododendron ‘Nobleanum’ displays its pink flowers intermittently throughout the winter, the season really begins with a few early bloomers like Rhododendron dauricum after Christmas and continues until Rhododendron ‘Polar Bear’ calls it a day in August. The main flowering period tends to be late April and early May. This unnamed plant was in full bloom in Durham botanic garden on 1st March 2009.

 

frosted rhododendron
‘More frost damage on an Early Rhododendron’

Tips to Avoid Frost Damage

    • There is no cure after frosting has occurred but waiting for next year.
    • Avoid planting in a frost pocket. Frost flows, like water, downhill
    • Plant under light shade which will offer some frost protection and the Early Rhododendrons will still flower and thrive.
    • For small specimen shrubs it may be worth covering with horticultural fleece if a cold snap is predicted.

Himalayan garden Grewelthorpe Rhododendron

Ancient Mariners Rhododendrons

Frost Hardy

This picture shows what I call the rime of the ancient mariner as I groweth one of three. Most Gardeners look after the great and small, both bird and beast……

Farewell, farewell! but this I tell
To thee, thou Wedding-Guest!
He prayeth well, who loveth well
Both man and bird and beast.

He prayeth best, who loveth best
All things both great and small; ……

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Rhododendrons and Scotland

Arduaine Garden in Scotland is well-known in international Rhododendron circles for the number of wonderful species grown here, many of which are considered tender elsewhere and grow unusually under a canopy of mature Japanese larch. To some people, rhododendrons are those unpleasant purple-flowered objects which clog up our native woodlands. This is but one species, Rhododendron ponticum or a hybrid of it which spreads rapidly both by seed and sucker.
Buds on Rhododendron Continue Reading →

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Rhododendron Sappho Labels

Rhododendron Sappho bud

I just purchased a new containerised Rhododendron named ‘Sappho’. The picture on the label is of white flowers with spotted purple centres. There are lots of buds, about 20, and they are looking lilac.  I thought of taking it back as that was not the colour I wanted.

Now the buds are opening I think it will be worth keeping and should fit in with my planting scheme.

Four Language Label

  • The label has minimal information but what there is can be translated. A pictured sun and sun half blached out must mean suitable for sun or partial shade.
  • A flower symbol V-VI implies it flowers late in May or June. Good that was what I was after and that seems to be how it is performing.
  • A vertical arrow and 1.5m says it will grow 4-5 feet high and possibly wide.
  • A complex symbol with a cross through it may signify no pruning
  • Strangely it is named as an Azalea for decoration do not consume. Submerge pot in a bucket of water for 10 minutes then plant in the garden. Fair advice.
  • The symbolic language may be classed as a fifth language since Esperanto never took off.

Rhododendron Sappho

Research on Sappho

  • Mauve buds open to lovely white flowers with a conspicuous dark purple, almost black, blotch.

Continue Reading →

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Blazing Deciduous Azaleas

Autumn is the best time to plant Azaleas so you get a blaze of colour next spring. If you want to see the colour before you buy than aim for a pot grown plant in spring.

Azalea & Aquilegia

Deciduous Azaleas have trumpet shaped flowers in a range of bright often fiery colours. The flowers appear before or at the same time as the leaves.

Types of Deciduous Azalea

  • The Ghent hybrids are generally fragrant plants growing 4-6′ tall.
  • Knapp Hill hybrids, Exbury and Mollis Azaleas do not have much scent but are available in vivid colours.
  • Occidentale hybrids have fragrant pastle coloured flowers in May.

Continue Reading →

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Lime Tolerant Rhododendrons

Inkarho Rhododendron

Inkarho Rhododendron

 

Whilst Rhododendrons have been regarded as ericaceous  plants unsuitable for alkaline or limey soils the newly bred Inkarho plants may be an exception.  It is also believed that some species and root stocks are tolerance of more alkaline conditions.

These German branded Rhododendrons have been developed to survive in soil which is less than perfect  for Rhododendrons. They are all grafted onto a stock that is lime tolerant like the old variety Cunningham’s White or R. hirsutum or R. ferrugineum. The root ball tends to be quite large and robust on these varieties and that may account in part for the ability to withstand alkaline soils. Not everyone is impressed with the results attributed to this breeding programme and particularly the reasons for lime intolerance see Non Conformist Rhododendrons by David Rankin  

His ‘suspicion is that there are in fact many more lime-tolerant species than we had been led to believe, or that at least there are tolerant strains. What we want to do next is to see whether these species growing on limestone are able to avoid absorption of calcium by their roots.’

I am happy to have the right soil for most Rhododendrons but here are a couple more pictures from Inkarho off spring.

Rhododendrons, which require a pH between 4.2 and 5.5but lime tolerant types  of root stock can thrive with a pH between 4.5 and 6.5. An added advantage of plants which have been bred on lime-tolerant root stock is that they are stronger on normal soils.

 

new-picture-22

 

RHS suggests other rhododendrons to try on alkaline soil:

R. augustinii (Electra Group) ‘Electra’ AGM
R. ciliatum
R. hippophaeoides
R.
‘Praecox’ AGM
R. triflorum

 

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What Kills Rhododendrons

It would be nice if your Rhododendrons were only to die from old age. Rhododendrons are generally long lived shrubs that would then outlive most of us and this article wouldn’t be needed.
However the natural world is not like that and accidents do happen. Gardener inflicted death can be caused by being over protective or trying too hard.

Rhododendron

What Makes a Rhododendron Die

  1. Rhododendrons are fibrous, shallow rooted plants that need good drainage to perform well and excess water is currently the major cause of death. Digging a big planting hole that creates a water sump is the way to drown your Rhododendrons.
  2. Rhododendrons do not have taproots to take a drink, unlike trees. Therefore Rhododendrons need frequent watering particularly when young or if spring is very dry.
  3. Another cause of rhododendron death is the excessive application of fertilizer directly at the base of the trunk of the plant. A good rule of thumb is to fertilize more frequently at lower concentrations rather than one large dose especially for small plants or newly transplanted plants.
  4. A fourth reason for rhododendron death is planting too deep. As indicated earlier, rhododendrons are shallow rooted plants and if buried they will stagnate or even die.
  5. Another reason that rhododendrons die is from cold winter temperatures with deep frozen soils. Most rhododendron can be grown in cold areas but I mulch around tender species.
  6. Not many varieties can survive unprotected all-day sun and some say they ‘are doomed’. In general rhododendrons in extreme climates benefit from filtered light and partial shade but there are some varieties that can stand direct sun.
  7. Sudden oak death fungus Phytophthora ramorum has recently infected Rhododendron ponticum and some container grown plants so this problem is moving up the chart of the causes of dieing.
  8. Fungus that causes ‘die back’ thrives in the same general conditions preferred by most rhododendrons. I am sometimes tempted to use a fungicide.
  9. Physical damage by rabbits, Deer or football playing grand children may cause breakages but should not lead to death.

Frost damaged Rhododendron

None Fatal Rhododendron Problems

Rhododendrons are a hardy species – they need to be coming as most do from the Himalayas
Frost has got to these rhododendron flowers but that is not cold enough to kill the plant.
Dried black buds may be caused by insect damage or water shortage.
Burned tips on this year’s new growth is typically indicative of lack of water as the plant withdraws water from the tips of the new foliage first.

June Rhododendron

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