Summer-Flowering Shrubs for August Pruning

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August presents an excellent opportunity for targeted pruning of many summer-flowering shrubs in UK gardens.

This practice not only promotes bushier, more aesthetically pleasing plants but also encourages a more prolific display of flowers for the following season.

Here’s a guide to some popular summer bloomers and their specific August pruning approaches:

Lavender (Lavandula):

This fragrant herb, often evergreen or semievergreen, produces stunning purple flowers during mid to late summer, complemented by its characteristic silvery-green foliage. All lavender varieties can undergo August pruning.

Following the flowering period, implement a light prune by reducing flowered stems by roughly one-third. This maintains a healthy form while encouraging further growth.

Buddleja davidii (Butterfly Bush):

This deciduous shrub is a magnet for butterflies, boasting fragrant, long flower spikes in vibrant hues of purple, pink, red, orange, and white, cascading from arching stems.

Varieties: All Buddleja davidii varieties benefit from August pruning.

For each flowered stem, implement a reduction of approximately onethird to half its length. Additionally, meticulously remove any dead, diseased, or damaged growth to optimise plant health.

Deutzia:

Deutzias are captivating deciduous shrubs showcasing clusters of delicate white or pink flowers adorning arching branches, typically blooming in late spring to early summer.

Focus on summer-flowering Deutzia varieties like Deutzia scabra and Deutzia magnifica for August pruning.

Once flowering has concluded, execute a light pruning to eliminate spent flowers. This encourages the development of a denser, bushier plant structure.

Callistemon (bottlebrush)

The flowers are produced on the tips of new shoots. Encourage bushy growth when young by tip-pruning after flowering in summer. Well established plants do not usually need routine pruning.

Laurus

Little or no pruning is usually required on informal shrubs, other than the removal of dead or damaged stems.

However, you can keep topiarized shrubs neat and rounded by pruning new growth back using a pair of secateurs. Bay laurel trained as standards will need any new shoots cut from the main stem. Hedges can also be trimmed for the second this time of year.

Other shrubs to prune include

Buddleja alternifolia

This elegant deciduous shrub bears its scented flowers on stems produced the previous year. So to ensure good flowering next year you need to prune immediately after flowering is over, which can be anytime from late June to the beginning of August. Remove any dead or damaged growth and shorten lop-sided or over-long shoots to balance the overall shape

Elaeagnus

Deciduous Elaeagnus angustifolia and E. umbellata varieties require little routine pruning other than the removal of dead or damaged stems..

Evergreen varieties of Elaeagnus x ebbingei, E. glabra, E. macrophylla and E. pungens require little pruning other than the removal of dead or damaged stems. Remove any plain greenleaved shoots as soon as they appear, cutting them back to their origin. Evergreen hedges can be trimmed at this time of year too.

Genista hispanica (broom)

To retain the plant’s bushy shape lightly trim the flowered stems immediately after flowering.

Do not prune back into woody stems because they are unlikely to re-sprout and never prune back hard since this may kill the shrub. Do not prune Genista lydia at all, since this does not respond to being cut back. Old and neglected shrubs are best replaced.

Ilex (holly)

Bushy evergreen hollies such as Ilex crenata as well as holly trees trained as hedges, such as the common or English holly, can be pruned to shape now that the growth has stopped but before the stems are fully ripened. It is important to leave the pruning of formal hedges to this time to avoid regrowth that will spoil the hedge’s neat outline.

Remove any plain green-leaved shoots on variegated varieties as soon as they are noticed, cutting them back to their origin.

Philadelphus

Several philadelphus can be pruned at this time of year.

You can prune mock orange (P. coronarius) now that flowering has finished to improve flowering for next year. Cut back flowered stems to a sideshoot that hasn’t produced flowers or to a plump bud. Alternatively you can prune in spring to get the best foliage displays.

To ensure good flowering on Philadelphus ‘Belle Etoile’ and ‘Virginal’ which bear their flowers on stems produced the previous year, prune immediately after flowering is over.

Pyracantha (firethorn)

Although pyracantha is normally pruned in mid-spring, wall-trained specimens can be pruned for a second time at this time of the year to expose the developing fruit to make the most of the berry display.

Sophora

No routine pruning is usually necessary, other than the removal of dead flowers or damaged stems. This is best carried out during midsummer when the cuts are less likely to bleed. Wall-trained specimens need tying into their support and any wayward stems cut back or removed completely. Old and neglected plants are best replaced.