PLANTS WORTH GROWING 75 
soil is essential, for stagnant moisture is apt to rot 
the crowns in Winter. 
Achillea. — We have wellnigh half a hundred 
species and varieties of Achillea, most of which 
have remarkably pretty foliage as well as flowers. 
A good proportion are suitable only for the Rock- 
garden, but the double forms of our native Achillea 
ptarmica stand in the front rank of flowers for cutting 
and as such are grown in vast quantities for market. 
' The Pearl ' has been a favourite for many years, 
but Perry's White is a more recent variety producing 
larger, broader-petalled flowers. 
Achillea Siberica is a beautiful and free-flowering 
plant, its single blossoms being perhaps more elegant 
than the double flowers of ptarmica varieties. This 
variety is frequently met with under the name of 
A. mongolica. A. millefolia is our common native 
Yarrow, the fern-like foliage and umbels of white 
flowers of which are so frequently seen amidst the 
grasses of our meadows, but the rose-coloured and 
cerise varieties of which there are now several are 
very ornamental and desirable garden plants. 
There are also the tall greyish-leaved A. filipendu- 
lina and its varieties bearing flat or convex corymbs 
of bright yellow flowers. This type may be grown 
to fine effect in the foreground of shrubberies or in 
soils that are too dry for many more fastidious 
plants. Division of the root clumps is an easy 
method of propagation of all the varieties except 
the miniature alpines. 
