This week Emma our head propagator at sissinghurst is writing a piece about her work in the nursery. Emma is responsible for propagating all the plants for sale in the shop and also for supplying plants into the garden.
She will be writing regularly for the blog about everything related to propagating plants and her role here in general.
If you have any topics you would like her to cover, please leave a comment for Emma below.
Enjoy her blog.
April is an incredibly hectic (but enjoyable) time of year in the nursery. The potting shed is a hive of activity with plants in various stages of their production being potted on, the final batches of seeds are being sown and the cutting bench is filling up with various delights from the garden.
The mild winter and sunny start to spring has been kind to the plants and they are growing well. Many plants are much bigger and lusher than you would normally expect at this time of year. Two amazing sights are our crop of roses, with many varieties producing flower buds already and our Pelargonium ‘Lord Bute’ which have been affectionately described as “monsters” due to their large size.
But, with the positivity of good weather came the unfortunate downside, that whilst the mild temperatures were kind to the plants, they were also kind to pest insects too. Pests such as aphids were able to continue breeding and feeding in glasshouses unhindered by natural predator insects such as lacewings and ladybirds which had gone into hiding for the winter. (The gardener’s tool shed is a favourite overwintering spot for adult lacewing).
So last month the nursery began its fight back against these pest invaders and we begun our program of biological control. The use of chemical sprays against pests on plants has been well documented for its pros and cons in recent years and sometimes growers don’t have much choice but to spray with chemicals to protect their crops. In our nursery I like to avoid spraying where ever possible and biological controls are my absolute favourite pest control of choice.
The process of biological control is to introduce insects into the crop environment (in a glasshouse or polytunnel) which would naturally predate on the pest insect. So a good example is ladybirds. Ladybird adults and Ladybird larvae will naturally hunt and eat aphids in their thousands as they are voracious predators and a highly effective means of control.
At Sissinghurst we introduce biologicals into our glasshouses and polytunnels at 3 week intervals from mid-March to late September. They are delivered in a box which has been kept cool. Temperature is important as at lower temperatures the biologicals are less active and will remain reasonably dormant until they are introduced into the glasshouse when the rise in temperature prompts them into activity. There are various methods of release of the biologicals depending on what type of insect they are. Some arrive in a bottle and once the lid is removed they simply fly out at will, some hatch over a period of time and are placed in the crop on small hanging cards until this happens and others arrive packaged in a mixture of vermiculite and this is sprinkled throughout the crops to release them.
Whatever their means of introduction these fantastic insects are an absolutely fascinating and effective way of controlling pest populations and are 100% natural. Here are some of the biologicals we use over the year at Sissinghurst.
The last image depicts a predatory beetle (Atheta coriaria)
A Fantastic biological pest controller, these beetles known as Staphylinids look like a miniature form of the Devils Coach Horse Beetle. They are fantastic general predators, but are extremely effective at controlling sciarid fly populations. These beetles are particularly interesting as they are released throughout the year from a “breeder bucket”. The bucket is located in the glasshouse on a bench with some shade from direct sunlight. The beetle population will consist of 30% adult beetles and 70% larvae, pupae and developing eggs at any one time and so throughout the season we have a continuous breeding population of predators. The beetles exit their bucket through holes in the side and are particularly active on warmer days.