Harpalium Rigidum.--A hardy perennial, producing very fine yellow
flowers in the autumn. It will grow in any good garden soil, and may
be propagated by seed sown in early autumn, or by division of the
roots. Height, 3 ft.
Hawkweed.--See "Crepis" and "Hieracium."
Heartsease.--See "Pansies."
Heaths, Greenhouse.--For their successful growth Heaths require a
well-drained soil, composed of three parts finely pulverised peat and
one part silver sand, free ventilation, and a careful supply of water,
so that the soil is always damp. If they suffer a check they are
hard to bring round, especially the hard-wooded kinds. Some of the
soft-wooded Heaths, such as the H. Hyemalis, are easier of management.
After they have flowered they may be cut hard back, re-potted, and
supplied with liquid manure. The stout shoots thus obtained will bloom
the following season. (See also "Ericas.")
Hedera.--See "Ivy."
Hedychium Gardnerianum.--A hothouse herbaceous plant, delighting in a
rich, light soil, plenty of room in the pots for the roots, and a good
amount of sunshine. In the spring a top-dressing of rich manure and
soot should be given. From the time the leaves begin to expand,
and all through its growing stage, it needs plenty water, and an
occasional application of liquid manure. The foliage should not be cut
off when it dies, but allowed to remain on all the winter. While the
plant is dormant keep it rather dry and quite free from frost. It
may be increased by dividing the roots, but it blooms best when
undisturbed. July is its flowering month. Height, 6 ft.
Hedysarum.--Hardy perennials, requiring a light, rich soil, or loam
and peat. They may be raised from seed, or increased by dividing the
roots in spring. H. Multijugum bears rich purple flowers. Height, 6
in. to 3 ft.
Heleniums.--The Pumilum is a very pretty hardy perennial that may be
grown in any soil, and increased by dividing the roots. It produces
its golden flowers in August. Height, 1-1/2 ft. H. Autumnale is also
easy to grow, but flowers a month later than the Pumilum, and attains
a height of 3 ft. H. Bigelowi is the best of the late autumn-flowering
species, producing an abundance of rich yellow flowers with purple
discs. Flowers in August. Height, 3-1/2 ft.
Helianthemum Alpinum (Rock Roses).--These hardy perennials are best
grown in sandy loam and peat, and may be increased by cuttings placed
under glass in a sheltered situation. Bloom in June or July. Height, 1
ft.
Helianthus (Sunflowers).--The tall variety is a very stately plant,
suitable for the background or a corner of the border. Well-grown
flowers have measured 16 in. in diameter. The miniature kinds make