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.