Lilacs
We have a number of Lilacs in the gardens, some of which have grown into mighty specimens. They are at their best in May. Not only to do they provide colour but are also delightfully fragrant. We mostly have varieties of Syringa vulgaris (Common Lilac). This is the species you are most likely to see just walking down the street. There are however many other species and hybrids to choose from. Many of which are of great garden value.
Like the Philadelphus we are collecting for the national collection, a great many varieties of Syringa vulgaris were bred by Victor and Emile Lemoine, in the late 19th century to the early part of the 20th century. It feels appropriate then, given that the gardens conception in the 1870s that we should have some of these Lemoine lilacs in the garden.
The ovaries in lilac flowers are often difficult to locate. It required the fine eyesight and steady hand of Mme. Lemoine to put S. oblata pollen on the S. vulgaris ovary correctly. The next year they recovered seven seeds. These seeds resulted in more specimens to work with and continue the breeding program. Syringa vulgaris ‘Azurea Plena’ although unassuming, has bluish double flowers. This was a key parent of the double flowered selections bred by the Lemoines. I am fairly confident that S. v. ‘Madame Lemoine’ is the large lilac near the Judas Tree. It has creamy yellow buds opening to fragrant, pure white double flowers. It is still a very highly regarded and a popular variety. Other firm favourites are, S. ‘Primrose’ pale primrose yellow, and S. ‘Katherine Havemeyer’ purple-lavender, fading to pale lilac-pink; broad compact panicles.
I am not so sure about the other specimens we have. Given the colours and locations they all appear to be deliberate. The double dark purplish red could be ‘Charles Joly’. As with many other plants that have succumbed to the specialist, far too many lilacs have been named – around 2000. Their differences are confined almost entirely to the colour of their single or double flowers and it takes a highly cultivated imagination to ascertain the various shades which alter from hour to hour, making identification difficult. We appear to have a small specimen of S. x josiflexa ‘Bellicent’. It comes from a highly beautiful race of hybrids bred by Miss Isabella Preston in Ottawa, Canada. ‘Bellicent’ has enormous panicles of clear rose-pink flowers.
In order to get Common Lilacs to flower at a hight that can be apricated, it is recommended to remove older stems to ground level. You can prune at any hight and new shoots will appear but for a more natural and elegant look, I prefer to go right back to ground level. Aim to remove about a third (one in three stems). Do this immediately after flowering as Lilacs will set their buds early and later pruning will remove these. If it is an old plant that needs renovating, pruning in winter-early spring will be easier, before the plant comes into leaf. Dead-heading makes little difference to the plant’s health, but does improve its aesthetics. To avoid biannual flowering (where the plant puts so much energy into flowering one year and needs a rest the next (an off year) follow Christopher Lloyd’s advice. In April, at the end of every branch you will find a number of strong, flowering shoots. One-third of these should be shorted back to a pair of leaf buds. These buds will make shoots that will flower in following ‘off’ year. The two-thirds that are left unpruned will provide ample blossom for the current year.
On the whole it seems to be a good year for Lilacs, enjoy the flowers while they last!