Gunnera Manicata (Chilian Rhubarb).--This hardy plant bears large leaves on stout foot-stalks, and is very ornamental in the backs of borders, etc. Planted in a rich, moist soil, it will flower in August. It can be propagated by division. Height, 6 ft.
Gunnera Scabra.--Has gigantic leaves, 4 to 5 ft. in diameter, on petioles 3 to 6 ft. in length. It prefers a moist, shady position, and bears division. Makes a fine addition to a sub-tropical garden, where it will flower in August. Height, 6 ft.
Gynerium (Pampas Grass).--This unquestionably is the grandest of all grasses, and is sufficiently hardy to endure most of our winters. It is, however, desirable to give it some protection. It requires a deep, rich, alluvial soil, with plenty of room and a good supply of water. Plants may be raised from seed sown thinly in pots during February or March, barely covering it with very fine soil, and keeping the surface damp. Plant out at end of May. They will flower when three or four years old. The old leaves should be allowed to remain on till the new ones appear, as they afford protection to the plant. It may be increased by division of the root. Height, 7 ft.
Gypsophila.--Of value for table bouquets, etc. They will grow in any soil, but prefer a chalky one. The herbaceous kinds are increased by cuttings; the annuals are sown in the open either in autumn or spring. They bloom during July and August. Height, 1 ft. to 3 ft.
Habrothamnus.--These beautiful evergreen shrubs require greenhouse culture, and to be grown in sandy loam and leaf-mould. The majority of them flower in spring. Height, 4 ft. to 6 ft.
Halesia Tetraptera (Snowdrop Tree).--This elegant shrub will grow in any soil, and may be propagated by cuttings of the roots or by layers. The pendent white flowers are produced close to the branches in June. Height, 8 ft.
Hamamelis (Witch Hazel).--An ornamental shrub which will grow in ordinary soil, but thrives best in a sandy one. It is increased by layers. May is its season for flowering. Height, 12 ft. to 15 ft. H. Arborea is a curious small tree, producing brownish-yellow flowers in mid-winter.
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 fine vase ornaments. They grow in any garden soil, and are easily increased by seed raised on a hotbed in spring and afterwards transplanted. The perennials may be propagated by division of the root. They produce their flowers in August. Height, 3 ft. to 6 ft.
Helichrysum.--Fine everlasting hardy annuals, that grow best in a mixture of three parts peat and one part sandy loam. May be readily raised from seed sown in a cold frame in March, or cuttings taken off at a joint will strike in peat and sand. Bloom during July and August. For winter decoration the flowers should be gathered in a young state, as they continue to develop after being gathered. Height, 1 ft. to 6 ft, but most of them are 2 ft. high.
Heliophila.--Pretty little hardy annuals, thriving best in sandy loam and peat. Sow the seed early in spring in pots placed in a gentle hotbed, and plant out in May. They flower in June. Height, 9 in.
Heliopsis.--This hardy perennial is useful for cutting purposes, the flowers being borne on long stalks, and lasting for two or three weeks in water. It is not particular as to soil, and may be increased by dividing the roots. Height, 5 ft.
Heliotrope.--Commonly called Cherry Pie. Sow the seed early in spring in light, rich soil in a little heat, and plant out in May. The best plants, however, are obtained from cuttings taken off when young, in the same way as Verbenas and bedding Calceolarias. They are very sensitive to frost. Flower in June. Height, 1 ft.
Helipterium.--A half-hardy annual, bearing everlasting flowers. It should receive the same treatment as Helichrysum. Blooms in May or June. Height, 2 ft.
Helleborus (Christmas Rose).--As its name implies, the Hellebore flowers about Christmas, and that without any protection whatever. The foliage is evergreen, and of a dark colour. When the plant is once established it produces flowers in great abundance. The plants of the white-flowered variety should be protected with a hand-light when the flower-buds appear, in order to preserve the blossoms pure and clean. Any deeply-dug rich garden soil suits it, and it is most at home under the shade of a tree. It prefers a sheltered situation, and during the summer months a mulching of litter and an occasional watering will be beneficial. Readily increased by division in spring or seed. Height, 1 ft.
Helonias Bullata.--A pretty herbaceous plant, bearing dense racemes of purple-rose flowers from June to August. It grows best in peat, in a moist position. It can be raised from seed or increased by division of the roots. Height 1-1/2 ft.
Hemerocallis (Day Lily).--Old-fashioned plants of great merit. Planted in large clumps they produce a grand effect. They are easily grown in any common garden soil, and bloom in July. Height, 3 ft. H. Kwanso has handsome, variegated foliage.
Hemp.--See "Canna" and "Cannabis."
Hepatica.--This enjoys a rather light, sandy soil and a shady situation. The roots should be taken up and divided every second year. Well adapted for surrounding beds or clumps of Rhododendrons. Flowers in March. Height, 4 in.
Heracleum.--Coarse hardy biennials, that may be grown in any kind of soil, and are readily raised from seed. They flower at midsummer. Height, 2 ft. to 4 ft.
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