Choosing the right plants for a garden takes time, money and commitment. With the right selections, a landscape can stay bright and beautiful through the seasons. Powerhouse Plants, (Timber Press Inc., 2013) by Graham Rice, will ensure any landscape can reach its potential of seasonal beauty and eye-catching appeal. This excerpt explains the growing habits and differences in iris varieties and the care needed for each.
Iris — perennial
• Spring shoots
• Spring to fall foliage
• Summer flowers
• Iconic combinations of flowers and foliage from spring to fall
When we think of Iris varieties, we think of glorious summer flowers in Van Gogh’s vibrant colors — dazzling then gone, for theirs is a single, short-season drama. But some irises have an opening act of rich purple spring shoots, or feature variegated foliage, bringing up to three distinct features to the garden in as many seasons.
The blue-flowered North American natives Iris virginica, largely from the south, and Iris versicolor, from the northeast, both feature emerging spring shoots stained in purple. Or grow Iris ×robusta ‘Dark Aura’, a hybrid between the two; it not only features new growth that emerges almost black, but the flowering stems are also black — from top to bottom — and carry violet blue flowers. This is a very stylish, if uncommon, plant.
Several irises with variegated foliage provide striking color from spring to fall. There are no readily available variegated forms of bearded irises, but two variegated leaf forms of Iris pallida are near, easy-to-find substitutes. ‘Argentea Variegata’ has foliage brightly striped in white along its length but produces its pale blue flowers only occasionally. ‘Variegata’ is striped in primrose yellow and flowers freely. The foliage is at its best in spring and again after flowering, when there is often a new burst of growth.
More adaptable is ‘Variegata’, the striped form of the British native yellow-flowered Iris pseudacorus. Although generally preferring wet soil, it will thrive in many perennial borders that go through short periods of dryness. Its yellow-striped leaves are brilliant early in the season but have faded to green by flowering time. A large clump is truly dramatic. Look out too for variegated forms of other water irises; there are white-striped forms of both Iris ensata and Iris laevigata with blue or purple flowers.
Iris care essentials
• Around irises with purplish spring growth, try low-growing bright and gold variegated Ajuga reptans ‘Toffee Chip’ or the creeping, yellow-leaved Lysimachia nummularia ‘Aurea’. Pair variegated types with another powerhouse perennial, Amsonia hubrichtii.
• Most prefer full sun and moist soil, although they often perform well, if less vigorously, in soil that, although not wet, is rarely dry. Iris pallida is happy in drier conditions.
• All benefit from deadheading and may need dividing and replanting after a few years. Most will need old foliage removed in fall.
Iris varieties
Iris ensata ‘Variegata’
Z5 – 8
34 × 24in
85 × 60cm
Iris laevigata ‘Variegata’
Z5 – 8
34 × 24in
85 × 60cm
Iris pallida ‘Argentea Variegata’
Z6 – 9
4 × 2ft
1.2 × 0.6m
Iris pallida ‘Variegata’
Z6 – 9
4 × 2ft
1.2 × 0.6m
Iris pseudacorus ‘Variegata’
Z5 – 8
4 × 3ft
1.2 × 0.9m
Iris ×robusta ‘Dark Aura’
Z4 – 9
32 × 24in
80 × 60cm
Iris versicolor
Z3 – 9
20 – 32 × 12 – 18in
50 – 80 × 30 – 45cm
Iris virginica
Z5 – 9
12 – 36 × 12 – 36in
30 – 90 × 30 – 90cm
Read more: Learn how to care for Hydrangea varieties and Butterfly Bush varieties
This excerpt has been reprinted with permission from Powerhouse Plants: 510 Top Performers for Multi-Season Beauty by Graham Rice, and published by Timber Press Inc., 2013. Buy this book from our store: Powerhouse Plants
