Traditional large flowered rhododendron hybrids have all the glamour of a lost world, just like the one immortalised in Downton Abbey. They are dramatic, colourful and exciting – definitely “drama queens”. Surely with such qualities they are going to be challenging to grow. Not so, they are really very easy and satisfying in the garden.
Two of my favourites come from a group of hybrids produced since the second world war called the Walloper Hybrids. These stem from rhododendrons that were taken to a safe haven in the USA during the war to ensure they survived. The city of Southampton was being heavily bombed and one of the best collections of new hybrids was riskily housed in the garden of Townhill Park, the home of Lord Swathling.
Lord Swathling’s talented gardener, Fred Rose, had an uncanny knack of creating exciting new varieties. Lionel de Rothschild had tried to lure him away to his rhododendron collection at Exbury on many occasions but with no luck! The 1939 seedlings were taken to a cluster of rhododendron breeders in the USA. The unnamed hybrids were split out between them and they awaited the results.
When they flowered the resulting hybrids were all they promised and inspired the American breeders to great things A new group of really large, early flowering hybrids was eventually created and were dubbed the “walloper” group because of their great size.
One of the results of crossing Rose's original hybrids with newer ones is a fabulous plant bred in 1981 called Horizon Monarch. It hales from the US and has the most dramatic, plump, rich pink buds which open surprisingly to a large, traditionally shaped flower truss of a wonderful translucent yellow. It is always a favourite with the public and usually plays a starring role in rhododendron displays at Chelsea Flower Show.
This and Markeeta’s Prize are real favourites of mine. Markeeta’s Prize is a lovely bushy shape, great for filling space and covering the ground, low maintenance and don’t need pruning. The flowers are a bright hot, really vibrant red and hold this fabulous colour even when fully open. It, like Horizon Monarch, is fabulous in a pot (see here for how to plant in pots) or is equally as effective in larger borders in shady areas of the garden.
Will’s Tip: Pinch out the old flowers on both varieties when they have gone over and for every one you pinch out you will have 3 or 4 fabulous flowers next year.
To top off the attractions of these two fabulous varieties they are two of the earliest large flowered rhododendrons to burst into flower in early May. They really will add a big splash of drama to your garden.