Iris chrysographes 'Black Knight'

Spring - early · Outdoors

Feed with slow release fertiliser

Apply a general purpose slow release fertliser around the plant in early Spring, scratching it into the ground. Keep rhizomes exposed.

Spring - late · Outdoors

Feed with sequestrol

If plants are acid loving and grown in soil with little acidity, or in a container, or are watered with limey tap water an annual feed with sequestrol (iron chelate) is highly beneficial. Follow guidelines on the packet. Will also 'blue-up' hydrangeas.

For hydrangeas that have good blue flowers in acid soil, this product can be used with alkaline soil to turn the flowers blue. This is most effective when the soil is neutral or just slightkly alkaline.

Spring-Autumn · Outdoors

Water to keep the soil moist

For best results, this plant needs soil that is always moist. Water deeply and regularly as soon as soil appears dry. Even for established plants in the ground, a dry week can cause problems with some soils. Check plants in pots more often, especially in hot weather. Or install an automatic irrigation system which will do the hard work for you, even when you are away on holiday.

Without regular watering some plants never fully regain their beauty.

Spring-Summer · Planting

Divide when congested

When rhizomes have become very congested they can be separated or cut. Dust any cut surfaces with a fungicide and replant them. Throw away any poor or diseased segments.

Outdoors

Water with rain water

This plant needs rain water or soft water (the minerals in alkaline or "hard" water are harmful). This is especially important for plants in pots.