RACEMOSUM (Starch Hyacinth).—­Rich dark-blue or reddish-purple flowers.  Very free-flowering and fine for massing.  It is similar to the Cape Hyacinth, but flowers in denser spikes.

Hydrangea.—­This shrub delights in a moist, sheltered position and rich soil.  It may be increased at any time from cuttings of the young side-shoots, 2 or 3 in. long, under glass, in sandy soil.  The old stems will also strike if planted in a sheltered situation.  The plants should be cut back when they have done flowering, and protected from frost; or they may be cut down to the root and covered with manure.  They are well suited for the front of shrubberies, and also make fine plants for pot cultivation.  The flowers are produced in June and July.  Height, 3 ft.

Hymenanthera Crassifolia.—­Ornamental evergreen shrubs, thriving best in a compost of loam and peat.  They are increased by cuttings planted in sand and subjected to a little heat.  Height, 6 ft.

Hymenoxys.—­Pretty little hardy annuals that may be easily raised from seed sown early in March in any garden soil.  They bloom in June.  Height, 1 ft.

Hypericum (St. John’s Wort).—­Favourite dwarf shrubs.  Any soil suits the hardy kinds, but they prefer shade and moisture.  These may be increased by seed or division.  The greenhouse varieties thrive best in a mixture of loam and peat.  Young cuttings placed in sand under glass will strike.  July is their flowering season.  Height, 1-1/2 ft. to 2 ft.

I

Iberis.—­See “Candytuft.”

Ice Plants.—­See “Mesembryanthemum.”

Ilex.—­See “Holly.”

Impatiens Sultani.—­Half-hardy perennials.  May be raised from seed sown early in spring on a hotbed, or later on in a shady spot in the open border; greenhouse culture, however, is more suitable.  They bloom in August.  Height, 11/2 ft.

Incarvilleas.—­Ornamental hardy herbaceous plants, of easy culture.  They are suitable for the border or the rockery, and will grow in any soil if not too dry and exposed.  The tuberous roots may be planted at any time in autumn, 4 in. deep.  I. Delavayi makes a fine solitary or lawn plant, its leaves being from 1 to 3 ft. long; the soft rose-pink, Mimulus-shaped flowers, which are carried on stout stems well above the foliage, appearing in May.  Care should be taken not to disturb it in spring, and it is advisable to cover the roots in winter with a pyramid of ashes, which may be carefully removed at the end of April.  Incarvilleas may be propagated by seed sown, as soon as it is ripe, in light, well-drained soil, giving the young plants protection in a frame during the first winter, with enough water merely to keep them moist.  Height, 2 ft.

Indian Corn.—­See “Zea.”

Indian Shot.—­See “Canna.”

India-rubber Plants.—­See “Ficus.”

Indigofera.—­Beautiful evergreen shrubs.  I. Australis has elegant, fern-like foliage and racemes of pink or purple Pea-shaped flowers in April.  I. Decora Alba bears its white flowers in July.  They require a sandy loam or peat soil, and greenhouse culture.  Cuttings of the young wood planted in sand under glass will strike.  Height, 21/2 ft.