This is a large, deciduous shrub which bears large, fragrant, lilac blooms in May and June. These are produced above ovate, mid-green leaves and compensate for the short flowering period.
It's received a RHS First Class Certificate and has been one of the mainstays of the British shrub border. It can be grown in any reasonable garden soil but must not be neglected.
An annual feed with a balanced fertiliser or a mulch of well-rotted garden compost is vital and both suckers and dead blooms must be removed.
Shrubs are deciduous or evergreen woody plants, and often provide fragrant flowers, berries and foliage. They are good for structural framework, and they can provide a wonderful shelter and food source for wildlife.
Planting and Conditions
Container grown shrubs can be grown at any time of year. It is a little known fact that shrubs planted in the autumn and winter will be easier to look after than those planted in the spring and summer, because they will have time to establish and become hardy in the cooler months.
Plant the shrub at the same depth as it was in its original pot. Planting too deeply can result in root and stem rot.
One of the biggest causes of death in new shrubs is drought stress, so keep it well watered until it’s established.
Make sure you loosen the soil prior to planting. Most shrubs are tolerant of most soil types as long as it is fairly well draining.
Most shrubs will grow happily in containers, but they will be much more demanding on feeding and watering than shrubs in the ground would be. They will also need potting on every couple of years so that they don’t suffocate or become stunted in their pot.
Aftercare and Pruning
Once established, shrubs generally do not require much water. However, at first they need careful, frequent watering and should not be left to dry out.
Shrubs in the ground are generally not demanding and in most cases, annual feeding with general purpose fertilizer will suffice. Shrubs in containers may need more feeding; usually from early spring until late summer.
Shrubs also benefit from mulching in order to supress weeds, conserve moisture and provide vital nutrients. Mulch also greatly improves soil conditions. Shrubs can be mulched in late winter, after fertiliser has been applied, but it can be mulched through autumn to late spring as long as the ground is damp.
All shrubs benefit from dead-heading once spent flowers become apparent. Rhododendrons and Lilac especially benefit from the removal of dead flowers.
Some shrubs may show signs of reverted growth or ‘sporting’. This is where random shoots of different leaves associated with the plant’s parentage begin to appear. Most commonly this is where plants with variegated leaves sprout pure green growths instead of variegated ones.
To control reversion, remove reverted shoots promptly to discourage them. Reverted shoots are usually much more vigorous than the variegated ones, and thus should be completely pruned out and cut back into wood containing variegated foliage.
Potential Issues
Although shrubs are usually very robust garden plants, they can sometimes start to decline with no apparent or obvious reason.
This will start with browning leaves, which could indicate plant stress due to lack of water or waterlogging, an establishment failure or, in the worst case scenario, honey fungus. Another cause of leaf browning is a high salt content in the soil. This could be a natural occurrence, especially if you live near the ocean, or it could be from over fertilisation.
To remedy a high salt content, cut back on fertiliser and step up your watering regime for the next few weeks. If you live by the ocean, this will be harder to remedy—but stepping up your watering will help to wash some of the salt away all the same.