Garden Guide: Iberis-Kumquat
Iberis - Kumquat
IBERIS sempervirens - Candytuft
PLANTING: Set plants out in the spring, spacing 8-12 inches apart. Choose a location in sun or light shade; a variety of soils will do, so long as they are well drained. MAINTENANCE: Water during extended periods of drought. Dead-head by shearing as blooms begin to fade to extend blooming period. Shear foliage as well to maintain desired shape, compactness, and appearance. Zones 4- 8.
ILEX crenata - Japanese Holly
PLANTING: Set plants 3 to 4 feet apart in full sun or light shade. The soil should be light, well-drained, and slightly acidic. MAINTENANCE: Water during periods of prolonged drought and prune out any unruly limbs. Fertilize with a balanced fertilizer in the spring. Zones 7-9.
ILEX species - Holly
PLANTING: Male and female flowers are borne on separate plants. Female plants should be planted for fruit, with at least one male for every 8 to 10 females within a 300-400 foot range for pollination. The Ilex is widely tolerant of soil types, but will perform best in a well-drained but moisture-retentive soil of acid reaction. The best form and fruiting will occur in full sun, but plants can also tolerate light shade. MAINTENANCE: Little pruning is required, except to remove weak or dead branches, and to keep at desired shape and size. (Exceptions to this are I. verticillata, whose older branches should be cut back periodically to ground level, and I. opaca, or American holly, which will benefit from a formative pruning in early spring.) Zones various.
PLANTING: Space plants 4 to 6 inches apart in moist, acidic, organic soil in partial to full shade. Plant so the rhizome is barely covered. MAINTENANCE: Water during periods of dry weather. Zones 3-9.
IRIS Louisiana Hybrids
PLANTING: Set plants 2 feet apart. Choose a location in full sun or, father south, in light shade. The soil should be moderately water-retentive to damp, with extra organic matter added. Cover the rhizomes with 2 to 3 inches of soil. An acidic soil of pH 6.5 or lower is a must. MAINTENANCE: Keep plants well watered during periods of drought. A balanced fertilizer, applied twice a year as new growth commences and two months prior to bloom, is recommended, as is a year-round mulch, particularly in the colder regions. Zones 4-9.
IRIS pseudocarus and virginica
PLANTING: Native to wet places such as the edges of ponds and streams, these Iris can also be grown in drier areas provided they receive ample moisture. Cover rhizomes with one to two inches of soil and space plants 2 feet apart in full sun or light shade. MAINTENANCE: Keep plants well watered during periods of drought and remove seed pods to prevent re-seeding. Zones 4-9.
IRIS sibirica - Siberian Iris
PLANTING: Set plants 15 to 18 inches apart in full sun or light, dappled shade, choosing a moisture-retentive, slightly acid soil high in humus. Firm soil down thoroughly around the roots and water in well. MAINTENANCE: Keep plants well-watered for the first few weeks after planting. When centers of the clump begin to die out and flower production goes down, clumps should be divided. This may occur every 6 to 8 years. When flowers have finished blooming, cut off bloom stalks. Remove dead foliage in fall. Zones 3-9.
ITEA virginica - Sweetspire
PLANTING: Set plants 3 feet apart in full sun or partial shade. Itea is widely adaptable to soil type, tolerating wet or dry conditions. Full sun and dry soil will produce more compact growth and more brilliant fall color. MAINTENANCE: Prune in early spring to remove weak shoots, old woody growth, and winter killed branches. In the north it should be pruned to ground level in winter, treating it much like a Buddleia. New growth will produce the next spring. Provide a mulch for winter protection. Zones 5-9.
JUNIPERUS cultivars - Juniper
PLANTING: Choose a site in full sun, preferably one sheltered from harsh winds. Junipers will tolerate most soil types, including acid, alkaline, or dry rocky soils. Mulching is strongly recommended. MAINTENANCE: Nearly carefree. Junipers will benefit from a year-round moisture-preserving mulch. Water during long periods of drought. Little pruning should be necessary, except to remove the occasional dead branch. Upright types, such as J. virginiana ‘Skyrocket’ should be bound up with burlap and twine in colder areas over winter to prevent snow from breaking open the tight columnar growth. Zones various.
KALMIA latifolia and cultivars - Mountain Laurel
PLANTING: Set out plants in a well-drained, acid, highly organic soil that is cool and retains abundant moisture, spacing to allow for ultimate growth. Kalmia flowers best in light shade to full sun (so long as ample moisture is available), but is essentially a woodland plant requiring shade in the southern portion of its range. MAINTENANCE: Kalmia are surface-rooting, so do not allow them to dry out, especially when newly planted. Water during dry periods, and apply a mulch to conserve moisture. Should the leaves become yellow or spotted with yellow, kalmia is likely suffering from chlorosis, a common condition where the soil is lacking in soluble iron. Addition of sulphur or aluminum sulfate will reduce the soil pH, and free additional iron to become available to the plant. Prune after flowering as necessary to shape. Zones 4-8.
KERRIA japonica - Japanese Rose
PLANTING: Set shrubs 4 to 5 feet apart. For best results, plant in sun or partial shade-the latter being preferable farther south. Choose a location where the soil is loamy and has been enriched with organic matter. MAINTENANCE: Keep plants well watered during periods of drought. We recommend a winter mulch, which will also assure that the branches remain an attractive bright green all winter. To renew plants, cut back weak branches and thin out old stems to the ground after flowering. Zones 5-7.
KNIPHOFIA - Red Hot Poker
PLANTING: Space plants 2 to 3 feet apart in moist but well drained soil in full sun or partial shade. MAINTENANCE: Mulch young plants for the first couple winters. Kniphofia tolerates heat and dry conditions once it becomes established. Zones 5-8.
KOLKWITZIA amabilis - Beauty Bush
PLANTING: Set out in spring, in full sun to light shade. If planting more than one, set 15 feet apart. Kolkwitzia is widely tolerant of soil types. It will thrive even in sandy soils, but good drainage is essential. MAINTENANCE: Water well during periods of hot, dry weather. Every year, after flowering is complete, remove the old canes by cutting them back to ground level. This will encourage prolific flowering. Zones 5-8.