Tall Bearded Iris:
Are not less than 700mm (27½") with many growing up to 1 metre high (39")
The flower are generally larger than most smaller varieties, and often flower later than them as well.
Bearded Iris in border
Bearded Iris in Close up
Miniature Tall Bearded Iris:
Range in height from 400-700mm (16"-27½")
Flowers should not be more than 150mm (6") in height and width.
When determining flower width, measure horizontally from the center of one fall to the center of an adjacent fall.
Standard Dwarf Bearded Iris:
Range in height from 200-400mm (8"-16")
Flowers should not be more than 100mm (4") in height and width.
Miniature Dwarf Bearded Iris:
Maximum height is 200mm (8")
Flowers should not be more than 40 75mm (1½"-3") in height and width.
Bearded Iris require a sunny or partially shaded position, and will grow in most garden soils providing it is lime free.
Poor flowering is usually caused by overcrowding and excessive shade, meaning the plants should be divided and re-planted in a more suitable environment.
To prevent this happening, clumps should be divided approximately six weeks after flowering every three to four years.
Doing it then should ensure that there is sufficient time to produce new growth for the following season.
Take care if hoeing around the plants not to damage to the shallow root system.
Deadhead the flowers regularly during the flowering season.
Cut the foliage off when it turns yellow.
Watch out for signs of leaf spot and rhizome rot (Week 21)
Badly drained soil may encourage soil-borne diseases such as soft rot or rhizome rot.
Leaf spot is a fungal disease that shows symptoms of oval brown spots, the spots eventually join together and destroy the leaves.
Rhizome rot will turn the rootstock into a slimy mass, leaf tips turn brown and the plant finally collapses.
Cut away all affected parts from infected rhizomes and apply a fungicide spray to control both diseases.
If ground conditions allow, fork in a general fertilizer that is low in Nitrogen at a rate of 50-100gms (2-4 oz) / sq metre.
Applying peat or bark mulch now will assist in keeping weeds at bay.
Prepare a site for new stock or divisions by digging over the site and adding well-rotted organic matter.
The ideal site should be in a sunny position, and be well drained.
If established plants have finished flowering and they have become somewhat overcrowded now is a good time to divide them.
This exercise should be carried out every three or four years.
Lift rhizomes with a fork, taking care not to damage the outer, newly-formed rhizomes.
Select the most vigorous rhizomes from the edge of the clump cut them off with a sharp knife into 150mm (6”) lengths.
Remove old leaves and flower stalks, and cut back any damaged roots.
Discard older rhizomes, which are usually found in the centre of the clump.
To prevent wind rock or excessive transpiration, trim the leaves by about a half or one-third their length before replanting into a well-drained, sunny spot.
Position each transplant so that at least two fans are facing in such a manner that each rhizome receives the maximum sunshine.
Plant firmly, with the top of the rhizomes just showing above soil level.
Allow a minimum of 300mm (12”) between plants.
Don’t let them dry out before becoming established.
Plant out new rhizomes horizontally in a sunny position 25 mm deep and 600mm apart, i.e. planted with the top surface exposed above soil level so that they receive maximum sunshine.
After planting, top-dress with a low-nitrogen fertiliser, and then again in spring (circa week 13)
To prevent wind rock or excessive transpiration, trim the leaves by about half, (assuming this has not been done already prior to purchase)
Don't let them dry out before becoming established.
If not done previously split overcrowded plants as described above.