SEEDS, with their hidden potential for transformation, have always been a rich metaphor. Jesus encourages us to plant seeds of faith. The Buddhist tradition, in teaching that we become what we think, relies on our watering our good seeds of understanding and compassion.

At Batsford Arboretum, in Gloucestershire, the head gardener, Matthew Hall, sowed some seeds weighted with significance last week. They had been collected from a species of holly tree, Ilex rotunda, that grew within a two-kilometre radius of the atomic bomb hypocentre in Hiroshima.

Matthew had read about the initiative Green Legacy Hiroshima (GLH), and thought it would be an honour to grow seeds from an A-bombed tree. GLH was set up in 2011 to safeguard about 170 trees that either directly survived the devastating blast, or sprouted as seedlings across the desolate landscape soon after.

The trees are all labelled “Hibakujumoku”, meaning “Survivor tree”. GLH has so far sent seeds to botanical gardens, schools, embassies, and other institutions in 25 countries. As well as the holly, they sent Matthew some seeds from a ginkgo tree that is more than 200 years old, and sits within Shukkeien Garden, Hiroshima — a place where many people fled to and perished after the atomic bomb in 1945.

Matthew sowed these seeds in June, and the resultant small saplings are doing well in the Batsford Arboretum.

Both the ginkgo and the holly seed required a period of chilling in a fridge to break their dormancy. This is a process called stratification. In nature, the cold is provided by winter, and the strategy ensures germination the following spring, when a long benevolent growing season lies ahead.

This is the perfect time of year to sow hardy annuals, and they are comparatively undemanding. The idea is that they germinate in the warmth and moisture of late summer-early autumn, overwinter as leafy young plants, and resume growth in the spring, flowering in late spring and early summer.

The cow-parsley tribe lend a lovely informal air to a border, and their flattish flower-heads contrast well with upright flower-spikes and rounded shrubs. The herb dill is a member, and, of course, has many culinary uses. If you are not likely to call on the latter, it is even better to choose its longer-flowering relative Ridolfia segetum. Then there is the delicate white-flowered Orlaya grandiflora, Ammi majus, and altogether chunkier Ammi visnaga. Opium poppies are a sure-fire choice, and come in white, pink, plum, and near-black forms.

And, finally, I would recommend that you sow some nigella for a dash of blue. These easy annuals have a tendency to self-sow; so if you are observant when weeding they can become a year-on-year feature in your garden.

It may not be the time of year that you associate with seed sowing, but there are many opportunities for renewal within the cycle of the gardening year.