Caring for agapanthus

Healthy agapanthus are seldom bothered by pest and diseases. In winter look out for mealy bugs with their tell-tale signs of white fluff in the central new foliage. These can be managed by squashing them, flooding with soapy water or diluted eco oils. If they become a serious problem, use a contact insecticide. At this time of year, red spider mites can also be a problem. These mites can be found on the underside of the foliage and can be difficult to see with the human eye. Hosing the plants thoroughly can reduce or eliminate them. If they become a serious problem, use a natra-soap or a miticide. In spring young foliage may be damaged by slugs and snails but the plants often quickly recover.

The most common problem with Agapanthus is rot. When day time temperatures exceed 35 degrees, its best not to water your agapanthus too often as it can promote plant and root rot. Plan to hydrate your plants ahead of any forecast hot periods. Other causes of rot include fertiliser burn from excessive use of fertiliser and poor drainage. To improve drainage, add a blend of loam and coir fines to the soil.

Feeding Agapanthus

As a general rule of thumb, use liquid fertilisers in Autumn and slow release fertilisers in Spring. Many agapanthus cultivars do not grow much over winter and fertilising at this time of year would be less effective. Applying fertiliser from October to March could not only cause fertiliser burning to roots and foliage but also potential loss of your plants.

Avoid fertilizing agapanthus plants with high nitrogen fertilizers in spring, which will force new leafy growth at the expense of flowering. 

If using a liquid fertiliser, make sure it is applied according to the supplier’s recommendation. In warmer areas it may be appropriate to only use half strength per application to prevent root and foliage burn. Never apply liquid fertiliser on hot days. The best time to apply is late afternoon or early evening and watered in sufficiently. Soaking the area will ensure the food gets to the roots for quick uptake and prevent excess salt in soil and potential root burn. For example, NPK: ~ 16-4-25 + trace elements.

Granular formulas should also only be applied according to the supplier’s recommendations and never heaped up at or near the base of the plants. It is best that granular fertilisers are worked into the soil around the root zone. For example, a general purpose NPK: ~21-2-6 + trace elements

If using an organic fertiliser, use one that is relatively balanced, for example, NPK: ~4-4-6.