88 ALPINE PLANTS. 
top-dressing, for the plant will grow worse 
each season, and will gradually die away. 
The clump should at once be taken up and 
replanted in fresh compost or on some other 
portion of the rockery (pull into small bits 
before replanting), where it will soon take 
hold and grow as vigorously as before; this 
should be done directly it ceases flowering. 
A little grit and leaf-mould may be used as 
a top-dressing, working it well amongst the 
shoots. If this cannot be done directly the 
flowering is over, it should be left until the 
end of August, which is a very good time. 
River sand must not be used for top-dressing, 
as it will cause a rust to come on the foliage. 
There are a great number of varieties of 
Saxifraga, but I have given the outlines of 
culture for the rarer and more difficult; the 
others are of comparatively easy culture. 
SEDUM BREVIFOLIUM, S. PITTONI, S. FARI- 
NOSUM, and S. CYANEUM are about the 
only species that require special treatment, 
being of smaller growth than some of the 
others. Give them a compost of gritty loam 
and sand in equal parts. These are suitable for 
the south side of a rockery on little ledges 
