Watsonia pillansii

Watsonia pillansii L.Bolus is widespread in the eastern (i.e. summer rainfall) part of South Africa at low and medium elevations. This wide geographic range is associated with variation in ecological requirements and plant size, but the flower colour is generally bright orange to orange-red.

Plants grown from seed recently imported from South Africa have unbranched stems to 1.2 m high bearing up to 22 flowers. They are evergreen, with new shoots appearing in late summer immediately after flowering and before the previous season’s leaves have died. Each flower has a cylindric tube 3.5 to 5 cm long and acute perianth lobes to 24 mm long that flare widely when fully open; the colour in this strain whose exact provenance is unknown is a rather weak orange-juice orange on the lobes and deeper on the outside of the tube. The anthers and pollen are cream.

pillansii

Watsonia pillansii is related to W. schlechteri in the section Watsonia, subsection Grandibractea.

The species has been in cultivation in Australia since the 19th century. Cultivars that may be selections of W. pillansii include ‘Flame’ (marketed by Lawrence Ball in the 1940s) and ‘Watermelon Shades’ (Cheers, 1997). Watsonia ‘Beatrice’ or the Beatrice Hybrids is a group name for various natural hybrids of W. pillansii (Eliovson, 1968) that were exported to Britain, America and Australia in the early 20th century. The name comes from Watsonia beatricis J.Mathews & L.Bolus, which was a taxonomic synonym of W. pillansii.

References

Cheers, G. ed. (1997) Botanica. (Random House Australia).

Eliovson, S. (1968) Bulbs for the Gardener in the Southern Hemisphere. (Reed: Wellington).

Goldblatt, P. (1989) The Genus Watsonia. (National Botanic Gardens: Kirstenbosch)


Watsonia fourcadei

Watsonia fourcadei J.Mathews & L.Bolus has been in cultivation in Australia since the 19th century but does not appear to have contributed to the pedigrees of any hybrid cultivars bred in this country. It is widespread in the mountains of the southern Cape but absent from the Cape Peninsula where it is replaced by the related W. tabularis J.Mathews & L.Bolus.

Plants grown from seed recently imported from South Africa have flowers in a range of pink shades from pale salmon with a darker tube to the medium pink shown in the photo. They are evergreen, making most growth in mid summer to autumn but flowering in October to December.

The flowers have an arched, narrow cylindric tube about 6 cm long and perianth lobes 26 to 32 mm long incurved to form a cup-shaped limb.

fourcadei

Reference

Goldblatt, P. (1989) The genus Watsonia. 148 pp. (National Botanic Gardens: Kirstenbosch) ISBN 062012517


Watsonia schlechteri

Watsonia schlechteri L.Bolus grows in the montane veld of the winter-rainfall parts of the Cape, South Africa. Plants grown from seed imported via Silverhill Seeds first flowered this year and are a good match for the lectotype of W. schlechteri.

schlecht

The flowers are orange-vermillion with perianth lobes to 23 mm long. The buds end in a slightly downcurved point. There are no staminodal ridges in the perianth tube, a character that distinguishes it from the closely related W. pillansii. However, the fresh leaves of these specimens lack the strongly thickened margins and midvein that are used as another distinguishing character; these are only evident in dried material.

W. schlechteri is one of the smaller watsonias, usually much less than 1 metre tall with leaves about 40 cm long. It flowers in late December to January, resuming growth from offsets soon after flowering while the previous season’s shoot may still be green. Thus it has some leaves all year, or non-flowering plants may be briefly leafless before the new growth starts in late summer. Goldblatt notes that flowering in the wild is conditional on the plants not being shaded out by surrounding vegetation.

Like other watsonias native to high altitudes, it is at risk of damage in the agonisingly hot, dry summers we get here at sea level in Adelaide. The problem is to give the plants sufficient light without excess heat, a tall order on days of 42°C with northerly winds.

Reference

Goldblatt, P. (1989) The genus Watsonia. 148 pp. (National Botanic Gardens: Kirstenbosch).


Pedigrees of the Cronin watsonias

The rediscovery of Mendel’s principles of heredity at the beginning of the 20th century inspired a surge of ornamental plant breeding by researchers, commercial nurserymen, and perhaps most importantly by individual gardeners.

John Cronin, Director of the Royal Botanic Gardens in Melbourne from 1909 to 1923, had a personal hobby of experimenting with the improvement of garden flowers. He aimed to demonstrate the application of Mendel’s laws to flower breeding, and encourage gardeners to make their own hybrids. He worked with Dahlia and other genera, but particularly the winter-growing South African watsonias, which he recognised as “everyone’s flower” – easy to grow, attractive, a natural for southern Australian gardens.

In a previous publication I lamented that the exact pedigrees of his Watsonia cultivars were lost with the destruction of his papers after his death in 1923. But now the National Library of Australia has come to the rescue with their wonderful resource of newspaper files at Trove. Cronin was a tireless populariser and communicator, speaking at the evening meetings of horticultural societies around the suburbs of Melbourne and giving interviews to journalists.

In the spring of 1904, while employed by William Guilfoyle at the Botanic Gardens, he crossed a pink Watsonia borbonica with W. borbonica ‘Arderne’s White’. This cross may be represented by the following formula (but note that the order is arbitrary, it is not known which was the pollen parent and which the ovule parent in any of the crosses discussed here):

borbonica × Arderne’s White

He noted that pink flowers were dominant over white in the F1 generation, as has been confirmed by other researchers. In spring 1907 he selected one F1 plant with tall stature, dense branching and large flowers. He crossed this with a purple Watsonia meriana and the widely grown red Watsonia aletroides, and also backcrossed it to W. borbonica ‘Arderne’s White’ to create three lines for further breeding:

1. meriana × (borbonica × Arderne’s White)

2. aletroides × (borbonica × Arderne’s White)

3. Arderne’s White × (borbonica × Arderne’s White)

Cronin’s appointment as Principal of Burnley Horticultural College in 1908 seems to have interrupted this work, and in the following year he succeeded Guilfoyle as Director of the Botanic Gardens. By 1913 he had time to resume his watsonia experiments, and on 20 March sowed seeds from his three 1907 crosses at the Botanic Gardens nursery. Six years is not an inordinately long time to store Watsonia seeds, but there would be some loss in viability which may have unintentionally favoured some genotypes over others. Cronin’s management of the plants was another possible source of selection pressure to produce watsonias adapted to Melbourne gardens: he left the corms in the ground over summer, and gave the plants no fertiliser or watering even though 1913-14 was a drought period.

This generation produced their first flowers in October 1914; Cronin stated that these resembled the 1907 selection in size and colour, and were inbred that year. I interpret this to mean that he produced an F2 generation in each of the three lines by cross-pollinating siblings, since selfing would have produced little or no seed due to incompatibility. Thus,

1. (meriana × (borbonica × Arderne’s White)) × (meriana × (borbonica × Arderne’s White))

2. (aletroides × (borbonica × Arderne’s White)) × (aletroides × (borbonica × Arderne’s White))

3. (Arderne’s White × (borbonica × Arderne’s White)) × (Arderne’s White × (borbonica × Arderne’s White))

Large numbers of these seedlings were raised in the main nursery of the Botanic Gardens. By October 1916 Cronin saw the first flowers of the inbreds, which had a wider range of colours than their parents. Some whites showed up, as would be expected from recombination, including some with flowers of improved size and form compared to the original ‘Arderne’s White’. The watsonias commercially released in the 1920s as the Commonwealth hybrids or “Watsonia Cronini” were selections from this generation.

Line 1 would have produced the many Cronin cultivars with a mixture of characters from W. meriana and W. borbonica. These often have subtle tertiary flower colours due to genes from both species influencing anthocyanin pigment production. Floral bracts are typically well-developed and obtuse, compared to the shorter acute bracts of W. borbonica. Examples include ‘Lilac Towers’, which is the most widely grown Watsonia in Australia today and may be the same as Cronin’s ‘Sydney’, and the one illustrated below which may be his ‘Maitland’.

maitland
Line 2 would have yielded flowers with long tubes and small lobes like Watsonia aletroides. The one illustrated here was discussed in a previous post.

watsq
Cultivars from line 3 are not interspecific hybrids, but selections within the species Watsonia borbonica and would include Cronin’s improved whites such as this, which may be his ‘Hobart’.

hobart2
This is the same breeding program that was reported in less detail by Pescott (1926) and Cooke (1998).

It’s significant that Cronin did not use a long breeding program: the cultivars released were no more than three generations away from the original genotypes that had been imported from Africa in the 19th century. As he was working with a perennial that is normally propagated vegetatively, he could stop at the F2 with its fixed heterozygosity. I have bred watsonias four generations on from these and other old cultivars, and can attest that hybrid breakdown soon appears. Some of the resulting plants had interesting extremes of flower shape or colour, many were dwarf or weak in growth, but few were gardenable.

In the spring of 1917 Cronin presented this data to the horticultural correspondent of The Leader, and was lecturing on flower hybridisation to amateur horticultural societies with his new watsonias as exhibits. The following year he gave an interview to The Argus, repeating that his new watsonias were produced by first crossing and then inbreeding on Mendelian lines.

-oOo-

Sources

Anon. (1917) Melbourne Botanic Gardens – New colors in flowers – The laws of Mendel. The Leader (Melbourne), Saturday 10 November 1917 pp.13-14.
Anon. (1917) Horticultural society. The Advertiser (Footscray), Saturday 15 December 1917 p.3.
Anon. (1918) Botanic Gardens Experiments. The Argus (Melbourne), no.22,553. Monday 11 November 1918 p. 6.
Cooke, D.A. (1998) Descriptions of three cultivars in Watsonia (Iridaceae) J.Adelaide Bot. Gard. 18: 95-100.
Pescott, E.E. (1926) Bulb Growing in Australia. (Whitcombe & Tombs: Melbourne).


Watsonia humilis

Watsonia humilis Mill. is endemic to the Western Cape area of South Africa. It is winter growing and summer dormant like many other South African irids, restricted to a particular fynbos association on seasonally wet clay and loamy alluvial flats.

Its original range in the Breede River Valley between Tulbagh and Worcester, and the lowlands between Malmesbury, Franschhoek and Gordon’s Bay, has been reduced by 98%. Two populations are known to remain: one of fewer than 50 plants in an urban reserve at Gordon’s Bay and a second rediscovered in 2012 in the Breede River Valley near Wolseley, more than 80 km away. A third population may still exist between Somerset West and Sir Lowry’s Pass despite bulldozing by vandals in 2011.

Although critically rare in its natural habitat, it is secure in ex situ cultivation around the world. At least one strain has been passed between gardeners in Australia since its first importation in the 1830s.

humilis

Watsonia humilis is in the section Watsonia, subsection Watsonia of the genus. It is distinguished by its small size, unbranched inflorescence, strongly keeled bracts with outcurved tips and stamen filaments no longer than the perianth tube. Its pale coloured perianth (pale pink to white, never red) suggests that it is adapted to insect pollination unlike its larger and usually red-flowered relatives.

This watsonia can be grown in the open garden here but to keep track of the corms I grow it in 20 cm pots, lifting and dividing each summer. It multiplies vegetatively and I have used it as the ovule parent in hybridization.

The common form in Australian gardens has white perianth lobes and a tube shading to deep pink at the base. The F1 hybrids with bright red flowered W. meriana Mill. have uniformly pale pink flowers, the intensity and hue of the pink (anthocyanin) pigmentation varying slightly between individuals. This result shows that white flowers in this species have a different genetic basis to the recessive acyanic mutants of other species: it suggests incomplete dominance, possibly with more than one genetic locus involved. This is to be expected if white flowers were a stabilised local adaptation in the source population, rather than a passing mutation as in W. borbonica ‘Arderne’s White’. These hybrids lack the outcurved bract tips of W. humilis, which may be the most useful diagnostic character for recognising it.

References

Goldblatt, P. (1989) The genus Watsonia. (National Botanic Gardens: Kirstenbosch) ISBN 062012517

Goldblatt, P., Manning, J.C., Raimondo, D. & von Staden, L. (2013) Watsonia humilis Mill. National Assessment: Red List of South African Plants version 2013.1. Accessed on 2014/1/28.


Watsonia hysterantha

Watsonia hysterantha Mathews & L.Bolus is endemic to granite outcrops on a small section of the western Cape coast, South Africa.

It is winter growing and summer dormant like many other South African irids, but unusual in flowering in autumn at the beginning of the growing season. This not hysteranthy in the strict sense of producing pre-formed flowers direct from a bulb before the leaves like Amaryllis and Nerine. Instead, corms that have reached a critical size in the previous year “bolt” when they start growth, producing a flowering stem with about 4 short sheathing leaves. Smaller corms produce a vegetative shoot with about 6 leaves to 70 cm long and no stem above the ground.. As in all the watsonias, growth is sympodial – meaning that growth is terminated by the inflorescence. Each corm therefore dies after flowering, but not before producing offsets below ground as well as seed.

A practical consequence in a warm autumn like we had in Adelaide this year is that, while the hysteranthous amaryllids were all late in coming into leaf and many missed flowering this year, Watsonia hysterantha did not wait for low soil temperatures but started growth in early March as normal.

Per the Royal Horticultural Society colour charts, the flower colour is RHS 40B; it’s quite literally miniate, or the colour of red lead oxide.

hysterantha

This watsonia can be grown in the open garden but to keep track of the corms I grow it in 300 cm pots, lifting and dividing each summer. It multiplies vegetatively, and the only difficulty I have found with its management is in maintaining a high proportion of flowering-size corms. My stock came from Bruce Knight of Sydney, who imported seed in about 1995. As it is endangered in its natural habitat and further importations may no longer be possible, it’s important that existing stocks in Australia are maintained. Another Watsonia species, W. humilis, is even more critically endangered but at least one strain of it has been passed between gardeners in this country since its importation in the 1830s.

Reference

Goldblatt, P. (1989) The genus Watsonia. (National Botanic Gardens: Kirstenbosch) ISBN 062012517


Watsonia angusta

I’ve had this watsonia for years, it’s old garden stock from Victoria and looked like just a nondescript seedling from open pollination. But it turns out to be a true species, Watsonia angusta Ker.

Like other watsonias from the winter rainfall zone of South Africa, W. angusta has annual stems and leaves that die after flowering and are replaced by shoots from the newly-formed basal corms. But as it grows in more-or-less permanently wet sites (Goldblatt, 1989) the time interval between shoot generations is shortened. The corms have no obligate dormant period and start producing adventitious roots whenever water is available. Flowering is later than W. meriana, in late spring to summer.

Watsonia angusta

Watsonia angusta

W. angusta has orange to red flowers. I’d describe this specimen as “tomato-red”, a hue hard to capture exactly even after tweaking the colour balance in a digital pic. Per the Royal Horticultural Society colour charts, the flower is RHS 40B overall, with the lower tube RHS 40A and the perianth lobes shading to RHS 32B. As the name suggests, a lot of things about it are narrow: the perianth tube, the thin pointed seed capsules, and the perianth lobes – although at 8-9 mm these are broader than in some wild populations.

Under garden conditions in southern Australia it could be kept green all year, but would look untidy with new shoots appearing between the previous year’s spent growth. I manage it by giving it a short dry rest in January, when it can be cut to ground level or dug up and divided before resuming watering just about now.

Reference

Goldblatt, P. (1989) The genus Watsonia. (National Botanic Gardens: Kirstenbosch) ISBN 062012517