Mighty oaks from little acorns grow

The children of Wicor primary school in Hampshire are Plant Guardians for Canna ‘Chou Chou’, presented to them by James Wong at Hampton court Palace Flower Show last year and as such they are eligible to attend our educational workshops.  Last year we also worked with the RHS seed department who offered to put on a session for us on seed collection and storage and Wicor school jumped at the chance of attending.

Louise, Amais, Archie, Dylan, Grace, Amanda

Archie, Dylan, Grace and Amais arrived with Louis and Amanda and were met by Heather and Lucy of the RHS seed team and taken to their HQ in the heart of the garden.  Lucy had laid out a selection of different seeds, including the giant cone of  Pinus coulteri  also known as the widow maker due to the drastic consequences of one falling on your head.

IMG_6271Other gentler ways of seed dispersal were discussed; sticky burrs which catch on animal fur, berries eaten by birds, cyclamen seed taken by ants to their nests, and  explosive capsules such as Geranium and Alstroemeria.


Examining the poppy ‘pepper pot’ mechanism for seed dispersal

It was a perfect day to collect seeds – dry and sunny.

Packing the kit bag
Packing the kit bag

Wearing gloves the children collected seeds of the winter aconite (Eranthis hyemalis) into plastic bags recording the name, date and location onto a tag which will stay with the seeds as their unique identifier.

Down to the beds around the glasshouse to collect seeds of  Trachycarpus fortunei


and into the Arid Zone where a large seed head of Puya mirabilis produced an avalanche of tiny seeds


and again the seeds are labelled.

Back at the office, the children were shown how to deal with berries which are kept in the fridge over the winter to break up the flesh.IMG_6382

Once the seeds have been cleaned using sieves of different sizes and grades

and dried if necessary in drying racks,


they are stored in a cold store


before being packed and despatched to members, or used in propagation in the garden.

If you have ever collected seed yourself you will know that a lot of puff is needed to get rid of the chaff – the team here at Wisley use an aspirator which does the job by blowing the lighter material up a central tube retaining the heavier seeds in the capsule at the bottom.

Before leaving the children were given some seeds for the school garden.


The afternoon group was a little more mature, with gardeners from Exeter University, (NC of Azara) Collection holders of Geranium and Albuca and a Plant Guardian.

In response to a question on viability Heather explained that seeds are generally kept for three years.  They are only taken when ripe from a variety of healthy plants.  The efficient cleaning removes as many pests as possible and then storage in dry, dark, cool (10 degrees) conditions maintains the dormancy.

The RHS have started doing some germination tests trying to replicate normal members’ conditions. Seeds such as Acantholimon which only stays viable for a few weeks have been taken off the list  and many plants in the Tropical Zone have recalcitrant seeds –  oily – so they can’t be dried out, so they aren’t offered.  Some seed is better sown fresh , but can be put into dormancy which then needs to be broken with periods of cold.

Some of the sorting is still done by hand, using blotting paper, tweezers and magnifying glass.  Comparison trays are used as a final check.  The online Seed Site was suggested by one of the participants as a useful resource.

The RHS is part of Index Seminum which offers seeds to botanical institutions in UK and EU but seed is not sent outside this area because of the stringent requirements for cleanliness and the  need for a phytosanitary certificate.

At the end of the seed despatch period the team do a stock check to see what is popular –   anything marked with a red spot.  Cut flowers are very popular at the moment and they ran out of Cosmos and Erodium and Thalictrum.  The residual seeds are given to fundraising groups, including Plant Heritage’s Seed Shop at Hampton Court Palace Flower Show.


Thank you Heather and Lucy – two workshops in a day is a tall order, and I am sure that the children in particular will be inspired to pass on their knowledge at school and see what they can collect from their own garden.