PLANT HEALTH OF CHRISTMAS ROSES, SNOW ROSES AND LENTEN ROSES

The health of Christmas Roses, Snow Roses and Lenten Roses is easy to maintain if you follow some principles. Helleborus plants are by nature very resilient. Nevertheless, there are some factors that help them unfold their full potential. The right location and absence of waterlogging are key to the vigour, strength and defences against pests and diseases of Christmas Roses, Snow Roses and Lenten Roses. Also, our breeders' extensive work over recent years has gone a long way towards making the varieties from the Helleborus Gold Collection^® largely resistant to pests and diseases. However, no plant can be absolutely safe against the forces of nature. Below, you find a description of pests and diseases that may occur.

PESTS OF HELLEBORUS

Aphids can occur on young plants, fresh leaves or flowers. Slugs and snails also like to nibble Snow Roses and their siblings. Relevant biological control agents available from garden retailers or proven household remedies can be applied to control these unwelcome guests.

The well-known, proven beer trap (or "slug pub") helps to keep slug and snail populations in the garden at bay. Aphids can be controlled in an environmentally friendly way by spraying the plants thinly with a home-made stinging nettle slurry. (Marie Luise Kreuter's natural herb garden).

In a hard winter, mice occasionally nibble the buds. There is very little you can do about mice in the garden, other than perhaps keeping a cat.

If the plants are dwarfed for no apparent reason and not even the best plant care is helping, they could be infested with root nematodes. Nematodes are tiny roundworms invisible to the naked eye. They tap the roots and interfere with the plant's water and nutrient uptake. Control is extremely difficult. The only realistic solution is to dispose of any plants that show symptoms in a waste bin to prevent the nematodes from spreading.

Also, thrips can populate the plants in autumn (these tiny insects are also known as thunder flies). Normally, nothing needs to be done against them, because they will disappear in the first frost as fast as they appeared.

Caterpillar feeding damage can occur on flowers and leaves in summer. However, it occurs only occasionally and does not normally require any action.

DISEASES OF HELLEBORUS

Diseases caused by fungi are very disagreeable, and, in the worst case, in addition to impacting appearance, they can potentially kill the plants.

Blackspot (Coniothyrium hellebori), is the most widely occurring fungal disease that can affect hellebores. As the name indicates, it can be identified by black spots on the affected parts of the plant that often spread from the leaf edges. Since the fungus can infest any part of the Helleborus plant, you should carry out a thorough disease control programme as soon as the first signs begin to show. First of all, thoroughly remove all affected plant material and dispose of it in a waste bin to prevent the fungus from spreading.

Following this immediate action, keep a very watchful eye on the affected plants in the near future. Plant health can be improved indirectly by transplanting affected hellebores to a more adequate location, because an excessively low pH value or an excessively moist place will encourage fungal diseases.

In spring, apparently healthy leaf stems can be infested with rhizome and stem rot. It causes shoots to fall over at the base without mechanical impact. The shoots have in this case basal brownish or blackish rotten spots. The problem can be caused by a variety of fungi, such as Pythium, Phytophthora or Rhizoctonia. Since control of these pathogens is difficult, make sure to provide the hellebores with good drainage as waterlogging tends to encourage the occurrence of these fungi.