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.
Spray overall: metsulfuron-methyl 600g/kg (4g) + glyphosate (200ml) + penetrant per 10L water. 3. Cut down and paint stump: slash leaves close to ground, leave on site to rot down. Treat freshly cut bases with metsulfuron-methyl 600g/kg (1g) + glyphosate (50ml) + penetrant per 1L water or a 3-5mm layer of picloram gel.
Clumps may harbour snails or slugs. Occasionally, foliage is attacked in summer or autumn by lily caterpillars. Squash caterpillars or apply an insecticide to control caterpillars. Plants that are stressed (for example by growing in too much shade or by dry conditions), can be attacked by mealy bugs.
If your plants have a serious infection, with a large amount of foliage affected, you may need to apply a fungicide, since the disease could potentially kill your plant – or spread to other ornamentals. You have several options, fungicides containing maneb, chlorothalonil, copper, or sulfur are effective.
A sprinkle of Sulphate of potash can also encourage flower quantity and colour. Avoid giving plants too much Nitrogen or you will encourage lush leaves at the expense of flowers. leave them for winter structure in the garden, or spray them silver or gold once dried as Christmas decorations.
Apply this to the soil surrounding the root system and spray liberally over the foliage. Reapply once a week over 3 weeks. Note: if applying on foliage it is recommended not to apply if temperature is above 30 degrees. DRY APPLICATION: Apply at the rate of 15g per square metre evenly over the soil.
Vinegar mixture can treat most fungal infections on any plant, without causing any harm.
Agapanthus are very difficult to control. They can survive mowing, grazing, insects, and spraying.
Fertilizer. Since agapanthus plants are frequent bloomers, it's a good idea to fertilize them twice a year—in early spring and again two months later. Give them a balanced granular fertilizer such as 10-10-10 or one slightly higher in phosphorus than nitrogen to keep the blooms going all season long.
– Agapanthus Diseases
Leaf spot, root rot, and anthracnose are the most common fungal diseases to attack the Agapanthus plants. All of them produce yellow, brown or black rot spots on the leaves, stems and roots of the plant. This is followed by leaf drop and the eventual death of the plant.
If you want the best success with fertilizing your agapanthus then use several different kinds. Rotate these fertilizers throughout the year for the best success. If you would like to use alternatives to commercial fertilizer then purchase Kelp Meal, Alfalfa Meal, or Epsom Salt.
To bloom regularly, fertilize agapanthus twice a year, either after blooming, in early fall (September in the Upstate, October in the Lowcountry), or in early spring (early March in the Lowcountry and April Upstate). A low-nitrogen, complete fertilizer that includes phosphorus is best, such as 5-10-15 or 8-8-8.
However, Agapanthus also needs well-drained conditions. Waterlogging, and excessive watering, can also cause issues. Roots may rot (and fungal diseases, see below, may be more likely to set in) when conditions are too damp.
You can sprinkle, spray, or pour the vinegar onto the soil or spaces. What is this? As vinegar temporarily changes soil pH, it may be harmful to garden plants and roots so avoid applying too close to those areas (though such an application used just once or twice should be okay).
Vinegar is non-selective, meaning it will damage any plants and turf grass it touches, not just the weeds you are trying to kill. When you spray the vinegar onto weeds, make sure it isn't hitting other plants. If that isn't possible, paint the vinegar onto the weeds with a brush.
The results of the study show that apple cider vinegar is the most economical product to treat Candidiasis and other fungal infections.
Apple Cider Vinegar as Rooting Hormone
Because of its acidic nature, ACV is a naturally occurring pesticide and fungicide. It promotes environments that are inhospitable to disease and pests, which allows the cuttings to devote its energy to producing new roots.
Because agapanthus plants spread quickly, they are regarded as an invasive weed in parts of New South Wales and Victoria. Your local council can provide guidance on growing agapanthus, which may include dead-heading flowers before seed dispersal.
Powdery Mildew: This fungus disease occurs on the top of the leaves in humid weather conditions. The leaves appear to have a whitish or greyish surface and may curl. Usually occurs if agapanthus is grown in a shady area.
Avoid overcrowding: Overcrowding can be detrimental to the plants' health, so it's important to thin out clumps of agapanthus every few years.