144 A LITTLE BOOK OF PERENNIALS 



Polygonum — Knot-Grass, Knot-Weed 



The Knot Weed is a very ornamental plant for any garden be- 

 cause the foliage is so beautifully tinted in Autumn. Some of the va- 

 rieties grow very high and greatly resemble Bamboo in growth. Poly- 

 gonum sachalinense is one of this type, attaining a height of from 9 feet 

 to 12 feet, with leaves 12 inches long and sprays of greenish-white 

 flowers. The stems are curving or arched. P. affine (Brunonis) is the 

 dwarf variety, growing 6 inches to 18 inches high, with bright, rosy 

 red flowers and beautifully colored foKage. P. amplexicaule grows 

 about 2 feet or 3 feet taU and has deep red flowers which come into 

 bloom very late in September and last until October. P. Sieholdii 

 compadum grows about 15 inches high, has small, glossy green leaves, 

 and the entire plant is covered with small white flowers. Most of the 

 varieties are in bloom from July through August. 



Uses. The Giant Knot-Weed is used mostly in wild gardens or 

 imder trees, where an immense shrubby perennial is needed. The 

 other varieties are grown in front of shrubs or herbaceous borders. 

 Some of the dwarf ones are used in rockeries. Any of these are very 

 efl"ective when planted in masses, especially along banks of streams or 

 in moist places. Some of the flowers are valued for cutting. 



Culture. Some Polygonums require a great deal of space, for 

 the plants are very large. They are moisture loving and should be 

 planted in places where the ground is naturally very moist and does 

 not dry out easily. They will grow almost anywhere, in any soil, and 

 need very Mttle attention. 



Propagation. They are propagated by seeds and division of the 

 plant. 



Potentilla — Cinquefoil, Five Finger 



PotentiUas greatly resemble the Strawberry Plant, especially in 

 the manner of growth and the fohage. This is a trailing plant which 

 covers the ground rapidly and sends out roots as it goes along. The 

 flowers are very showy, the colors are very bright, with reds, oranges 

 and yellows predomiQatuig. These flowers are both double and single 

 and are borne in great profusion from June to August. The single 

 blooms look like a Buttercup or a Strawberry flower. Potentilla 

 airosanguinea, a parent of many lovely varieties, has single, rich 

 primson blossoms. Miss Wihnott is cerise, and WiUiam RoUison 



