Love of sowing the seeds


GROW:Harvesting seeds in preparation for sowing can be a messy business, but it’s also fun and rewarding, as Thérèse Duffey of Nightpark Nursery discovered

ALL SUMMER LONG I’ve watched and waited as the smartly striped, purple-and-white flower-spathe of my pot-grown cobra lily (Arisaema consanguineum) has slowly transformed itself into a plump, scarlet fruit that dangles heavily from the faded flower stem – a strangely wondrous process, as well as an unsentimental reminder that, in the lifecycle of a plant, survival of the species is everything. Now, much like the horticultural equivalent of a midwife, I’m hoping to help the process along by harvesting the ripe berries and preparing them for sowing.

As long as you follow some essential rules, seed-saving in this way can be one of the most satisfyingly frugal pleasures of gardening. But it can also be the foundation of a successful, family-run business, as proven by Thérèse Duffey, co-owner with her husband Michael of the wholesale, Kildare-based Nightpark Nursery (

Remarkably, almost all of the 500 species of plants sold by Nightpark are propagated from seed. Even more impressive is the fact that much of this seed comes from Nightpark’s own “mother stock” (the term for the nursery’s reserve of stock plants grown on site) as well as from gardens all over Ireland, hand-collected by Duffey’s loose but loyal network of family, friends, private gardeners and fellow professional horticulturists.

Every year, from mid-summer onwards, one of Nightpark’s giant light-filled greenhouses begins to fill up with trays of these different seed heads, pods and berries, which are brought indoors to gently dry. Some, like the faded flower-heads of Euphorbia characias, offer up their pale green seed very readily when simply left upturned in a tray lined with newspaper. More fleshy stuff, such as the stinking yellow fruit of the Arum lily (Zantedeschia aethiopica) gathered by Duffey in several mild Cork gardens a few weeks ago, requires a bit more work before it’s ready to sow.

“Preparing the seed of Zantedeschia is a messy business. First, you have to let it fully ripen and go mushy, which is why we always pile a heap of it together. Come November, we’ll wash the flesh away and rinse the seed several times before letting it dry out.”

Likewise, the plump red hips of Rosa glauca must be soaked in water for at least a week before it releases its sticky store of seed, which Duffey and her sister-in-law Fiona (a qualified environmental scientist) then spread out to dry before sieving it through one of a variety of graded screens. As for the wispy seedheads of ornamental grasses such as the red-hook sedge (Uncinia rubra), the best way to loosen their barbed seeds from the awns is by threshing them – a time-consuming process generally carried out in the nursery by hand in early autumn. These will be stored in an airtight container in the nursery fridge before being sown into a perlite/peat mix in late autumn or early spring.

As for the kinds of plants that Nightpark grows from seed, almost all of them are species rather than named cultivars, for the simple reason that only some of the latter will come true from seed. Likewise, Duffey also avoids collecting seed of named F1 hybrids, which never breed true.

Cost-cutting aside, the benefits for gardeners of such seed-saving endeavours are many. For example, Duffey has found that many plants traditionally perceived as being horribly tricky to propagate from seed have a far higher success rate when sown fresh, including hellebores, whose seed she collects in early summer just as it reaches ripeness. Stored in a sealed plastic bag filled with damp compost, it generally shows signs of germination after six to nine months.

Growing plants from saved seed sourced as locally as possible also helps to preserve at-risk species, promotes genetic diversity (unlike cuttings, which produce clones) and reduces the risk of disease. But perhaps best of all, it’s hugely enjoyable.

Plants whose seeds can be collected in the coming weeks

Thalictrum delavayi, many Eryngium species, Zantedeschia aethiopica, including Z. ‘Crowborough’, Watsonia sp, Iris foetidissima, Verbena bonariensis, V. hastata, Piptanthus nepalensis, Morina longifolia, Lobelia tupa, Eucomis sp, Tulbaghia violaceae, Agastache sp, Phlomis russeliana, some Hypericum species, Kirengeshoma palmata, Stobilanthes sp, Nerine sp, Sisyrinchium striatum and Dahlia sp.

Some rules of seed-saving

Be observant: the seed of some plants (such as Astrantia) ripens earlier than you’d think. The trick of successful seed-saving is in timing it correctly.

Always harvest on a dry, still day, and place seedheads/pods/berries into a clearly labelled (name, date, location) paper bag. Wear gloves to protect against allergic reactions.

Concentrateon the seed of species rather than named cultivars, many of which don’t come true. Avoid named F1 hybrids, which won’t come true.

Onceprepared and properly dried (this is crucial), store seed in the fridge at 5 degrees, in a labelled, zip-locked plastic bag that includes a silica gel pack.

For adetailed guide to the specific sowing requirements of individual species, see the online catalogue of seed suppliers, Jelitto (, see “Plant Information”)

Garden designers/exhibitors wishing to stage or sponsor a garden for Bloom 2013 should note that the closing date for receipt of completed applications is Thursday, October 18th. Contact Louise McLoughlin at louise.mcloughlin@bloominthepark.comfor more details.


The Garden and Landscape Designers Association (GLDA) are holding a one-day design event entitled ‘Guilty as Charged: taking responsibility for our design legacy’ on Saturday, November 10th. Key speakers are Graham Hickey and Dr Christie Boylan. For details, see

Lavistown House in Co Kilkenny are holding a one-day course (13th October, 10am-5.30pm) on mushroom-foraging. €80 including lunch and coffee. See lavistownhouse.ietel: 086-8407754

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