Contents

Breeding Delphiniums with Blue Flowers
Breeding Delphiniums with Dusky-Pink Flowers
Breeding Delphiniums with White Flowers
Delphinium Seeds available in 2008 from Seedsmen
Raising Delphiniums from Seed

General Introduction

One of the greatest joys in gardening is to watch the first flowers develop on a plant you have raised from seed. This is true whatever the source of the seed but it is especially exciting when that seed resulted from your own efforts at hand-pollinating the flowers of a favourite delphinium. The opening buds hold the answers to all those questions you have asked for the past twelve months, such as:

• Will the colour be as anticipated?
• Will the sepals be well formed?
• Will the eye be like that of the pollen parent you used?
• Will the bloom be long and regular?

Most of the delphinium seedlings we raise are never seen outside our own garden because few ever fully meet the standards we set ourselves. Even so, many seedlings have beautiful flowers with a wider range of colours and form than is available in delphiniums from a Garden Center. Here we share some of the good flowers that we have raised and also some of the failures.

Growing from Seed

An advantage of delphiniums is that the generation time is short. It is easily possible for the amateur hybridist to make a cross in June/July, the normal flowering time in England, and then see the flowers of the seedlings during the summer of the following year. The period can be shortened by sowing the seed immediately it is ripe in July or August. We do not do this because we lose too many small seedlings due to botrytis (grey mould) in autumn. There is also a tendency for seedlings that go dormant during the winter to 'bolt' to flower, which results in unrepresentative miniature blooms. We therefore store the ripe seed in a refrigerator until required and sow indoors in early spring.

February sown seedlings, like those seen here at 5/03/01, then grow without a check and normally produce full-size blooms from early August onwards. These tiny seedlings each produced a bloom about 1m (3ft) long in August or September! Unfortunately 25% of the seedlings grown in 2002 failed to produce a flower stem at all despite developing into very large plants. This frustrating situation is partly due to weather conditions but is primarily a characteristic feature of the particular crosses grown. It is a fairly common problem with seed from delphiniums having dusky pink flowers. In 2004, for example, 75% of the seedlings from a cross using 'Summerfield Diana' had only a basal rosette of very large leaves at the end of the season and did not flower. They all had to be kept another year but then several of the blooms were exhibited at the Delphinium Society Show, one being judged best bloom in the Show!

The growing procedure used is described in the Delphinium Society's illustrated cultivation leaflet "Delphiniums from Seed to Flower in Six Months". This costs £0.75 / $(US) 2.0 (price includes postage) and can be obtained from the Membership Secretary of The Delphinium Society.

Typically, our seedlings are pricked out into individual pots during the first two weeks of April, and seedlings are ready for planting out in late May, as seen in the picture. These seedlings were planted in the open ground between May 26th and June 14th 2004. Many of the plants had expanding spikes in early August with a few florets showing colour.

Ground preparation is best done during winter and spring when possible. With a limited amount of space in our garden, the beds where the seedlings are to be planted start the year filled with the seedlings grown last summer. The first task is therefore to replant selected seedlings as soon as they start into growth but only when the weather and soil conditions are suitable. We then clear out unwanted plants and incorporate compost or manure into the planting sites. In 2004, a light dressing of Blood, Fish & Bone fertiliser was incorporated in the soil when preparing the ground for the new seedlings. The plants selected in 2003 were moved to new flowering sites in late-February 2004 but long dry spells and dull weather meant they did not grow well until after watering and mulching in early June.

Seedlings are planted in rows 45cm/1.5ft apart, with a spacing between plants of about 30cm/1ft, as each plant produces just one flower stem (sometimes 2.5m/8ft tall). Blooms are supported by running twine between canes inserted between plants in a row. A plot approximately 10m/30ft x 5m/15ft provides space for about 200 plants and we aim to grow about 400 seedlings a year.

We normally expect to spray plants at least twice with a systemic fungicide to control mildew and sometimes spray with a systemic insecticide to control caterpillar infestations that can seriously damage developing flower spikes during August. In 2003, some seedlings were seriously damaged by voles (small rodents) eating young flower stems and leaf stalks. This happened again in August 2004 when voles were seen running among the plants during the day. We have been told of similar activities by voles damaging delphiniums in the USA!

Moving house and garden in 2005 disrupted these long-established routines, as there was no garden ready to take seedlings. Instead, seedlings were repotted into 2litre pots and grown in them throughout the summer. About 200 plants were grown, with the pots standing on Mypex sheet (woven ground-cover fabric) laid over turf in our new garden, with the grass first being shaved off as short as the mower allowed. During July, the pots could be watered only twice a week. It was therefore essential to shade the pot standing ground and to surround the area with wire netting to prevent rabbits destroying the plants. Despite the difficulties, the plants survived and almost all flowered providing some indication of flower quality, even though blooms were very small compared to seedlings grown in the open ground. Seedlings were again grown and flowered successfully in 2 or 4litre pots in 2006 due to problems in preparing new areas for planting. The worst aspect of the method is the time taken in watering the pots to keep the plants alive in such a hot summer.

In 2007 we returned to growing most of our seedlings in the open ground. We experienced an unusually high number of losses in one plot that seemed to be associated with flooding of the plant root after watering with a sprinkler soon after planting out. A high proportion of seedlings from parents with dusky pink flowers again failed to produce blooms and will need to be looked at in 2008. Despite such problems, several of the seed batches produced seedlings showing promise and flowers colours were superb.