HAVE a large xeronema which has been growing in the same raised
bed for 25 years where it has thrived with dark glossy spears and
lots of flowers. However, over the last six months or so it has
started to show brown rot at the base of each group of spears and
the entire plant is collapsing. Even a piece I took off two to three
years ago and planted some distance away has started showing the
same symptoms. Could this be a fungal disease?
aka Poor Knights lily, require extremely free-draining conditions
and can go for months without water. A mistake many people make
is in thinking you can make them grow better and faster by watering
According to well-known
plantsman Terry Hatch, watering xeronemas in hot weather can cause
root problems and rot at the base of the plant. He recommends the
fungicide Foschek for controlling root diseases of this type - it's
available from horticultural suppliers such as Veg-Gro Supplies
Ltd. Or you could try No Root Rot, stocked by most garden centres.
Follow the label instructions.
Otherwise, allow the
plant and soil to get as dry as possible and, instead of watering
in summer, apply a mulch of granulated bark or pebble chips which
not only improves soil condition but reflects heat in a similar
way to the rocky areas where these stately plants thrive on the
Poor Knights and Hen Islands. They also require exposure to full
sun, so check if nearby shrubs or trees are casting shade and prune
Gardener, Issue 172, 2005, Page 24
Reproduced with permission from the former Weekend Gardener magazine. The views expressed here are not necessarily those of the RNZIH.