Looking after Holly and Viburnum tinus topiary

Containerised topiary plants rely on you for all their feed and watering requirements. Feed with a general purpose fertilizer such as Vitax Q4 once a month from Apr -Jul. Discolouration of foliage is usually due to lack of feeding.
Pruning: As a minimum, prune topiary during early June then again in October to shape it up ready for winter. Alternatively, trim little and often throughout the growing season. Use secateurs to avoid leaving cut leaves. Prune Viburnum tinus after flowering if necessary but bear in mind that the flowers will go on to produce very attractive berries for the autumn-winter. 

Don't rely on rainfall to water containerised topiary; the foliage is so dense that little if any rain would reach the soil. Luckily however, holly is a very tough plants. Water container grown plants throughout the growing season (Apr-Sept). The frequency very much depends on the sun/shade situation of the plants and the weather conditions. Waterlogging can also be a problem if the container does not drain between waterings.

Discolouration of foliage is usually due to feed and/or watering requirements - see above. On holly, low numbers of yellow leaves is part of the natural shedding process; these can just be picked off if too unsightly. However, if an excessive amount of yellow leaves appear this can be a symptom of waterlogging - check the compost.

 Holly (Ilex) and Viburnum tinus topiary is very adaptable; being happy in full sun, part shade or full shade. Watering just needs to be adjusted accordingly. Holly and Viburnum tinus suit all soil types apart from waterlogged! In a container, a soil based compost such as John Innes No.3 with added organic matter and coarse grit to aid stability and drainage would be ideal.