proteas With Altitude Annual Report January – December 2019 Robbie Blackhall-Miles and Ben Ram Abstract This report aims to show how the ‘proteas With Altitude’ project progressed during 2019. It is an opportunity to review the ongoing process of setting up the nursery site, analyse data gathered about the species grown and set aims for the year ahead. Background ‘proteas With Altitude’ is an ongoing research project studying the horticulture of Proteaceae in the UK. In 2015, an initial expedition was undertaken to study in-situ plants and collect seeds of Proteaceae, growing at high altitude, in the Western Cape of South Africa. One hundred and fifteen separate observations covering fifty-five distinct species were made, of which thirty species were collected as seed. A further collecting trip was made during December 2017 with 43 species being collected as seed, of which 16 were new to the project and 6 new to cultivation, and plants and cuttings of some species being imported under phytosanitary certificate. A full report detailing progress up to the beginning of 2019 can be found in the 2016, 2017 and 2018 annual reports. This report will discuss the period between January 2019 – December 2019. Nursery Infrastructure Drip irrigation to 1L pots has worked well but watering of large potted plants is better by hand (with a watering can or hose), due to lack of water pressure. As plants in 1L pots have been potted up into 2L pots, some of the drip irrigation lines needed adjusting to accommodate these taller pots; there is currently capacity to do more of this. A 1000L water storage tank has been installed to collect rainwater from one side of the roof of the large polytunnel. This has been used for siphoning into troughs which are used to fill watering cans with. Purchasing a hose adapter for this water storage tank is planned for 2020. Since the cheap and unreliable weather station at the nursery broke, no rainfall has been recorded there and only winter minimum temperatures have been recorded. A more reliable way of recording weather data at the nursery is needed, using a more robust weather station. The weather station we have been able to afford in the past is the Clime Met CM2000, which costs £150. This is a useful weather station as it records data wirelessly and the data is easy to extract, also being connected to the internet allows viewing of current and past weather. It relies on batteries, however, which run out without warning and result in no data being recorded from that point on. Labelling of plants that have either been potted into large terracotta pots or into the ground has been improved. Data on these labels is now printed and includes collection number, species, collection location and altitude, see photo on right. Germination Efforts to germinate seed in 2019 were concentrated on species which have previously proven difficult. This meant that of the 36 seed batches sown, only 10 batches had any germination. Failures Protea repens and Protea amplexicaulis again failed to germinate, even though the same method was used which has been successful with other members of this genus. Whether the issue was with seed viability or germination method remains to be seen, although the former is suspected. Leucadendron singulare also failed to germinate again. This species only grows on very high summits (approx. 2000m) and may need a cold stratification. No germination of Mimetes, Sorocephalus or Paranomus was again a disappointment. Although Protea recondita had a 40% germination rate, all the seedlings died, which may have been due to damping off. Successes Protea scabriuscula – A 54% germination rate was achieved. This was done by soaking seed in smoke-disk water for 24 hours and exposing sown seed to a day/night temperature swing of 5°C/20°C. A 28% seedling mortality rate means that 5 plants of this species now join the living collections. This is enough plants for trialling in the ground as well as growing in a large pot. This also completes the group of 4 species of high altitude ‘Snow Proteas’ (Paracynaroides) which are grown at the nursery. The 5th species of this group, Protea lorea, grows at lower altitude but we will be germinating this species in 2020. Leucadendron arcuatum – A 90% germination rate was achieved. This was done by soaking seed in smoke disk water for 24 hours and then GA3 for 36 hours, before exposing sown seed to a day/night temperature swing of 5°C/20°C. A seedling mortality rate of 56% means that only 4 plants remain. The mortality was due to caterpillar damage. It is hoped that this sprawling, mountain growing ‘Arid Conebush’ will do well in a sunny, well-drained rockery once it is large enough to be planted out. Aulax cancellata – A 90% germination rate and only one death means that 8 plants of this species are doing well in 1L pots. Germination was achieved by soaking seed in smoke-disk water for 24 hours and exposing sown seed to a day/night temperature swing of 5°C/20°C. Leucospermum winteri – A 35% germination rate was achieved. This was done by first removing the outer two seeds coats, then subjecting the seeds to a dry heat of 45°C for 15 minutes before immediately immersing into 18°C water to cause micro-fractures in the remaining seed coat. The seed was then soaked in smoke water for 24 hours and a further 24 hours in GA3, before exposing sown seed to a day/night temperature swing of 5°C/20°C. A seedling mortality rate of 14% means that 6 plants of this species can be trialled at the nursery. This is very exciting as even though the seed was collected at only 466m, the altitudinal range of this species goes up to 1300m, so may have some genetic cold tolerance. Leucospermum erubescens – Although this is species does not grow much above 600m, having been collected on the Robinson Pass, which does occasionally get cold, it is hoped that the one seedling which germinated will do well at the nursery, although it may need to stay in a large pot. Germination was achieved using the same method as for Leucospermum winteri, but a higher dry- heat of 55°C was used to crack the final seed coat. Spatalla nubicola – Two batches of seed from different collections of this species were germinated with 15% and 17% germination rates achieved for each. Both batches were treated in the same way. A significant proportion of the seed collected contained no embryo; this was clearly made visible by SEM imagery produced as part of a collaboration with artist Raji Salan (see 2018 report). Effort was made to choose seeds without one end looking acute and collapsed. Painstakingly, the eliasome at the end of each small seed was removed with the assistance of a fine needle. This was followed by soaking seed in smoke disk water for 24 hours and then GA3 for 36 hours, before exposing sown seed to a day/night temperature swing of 5°C/20°C. A very high mortality rate, possibly due to aphids, has left only one seedling still alive of this species, see photo on right. Since this is the first time this species has ever been cultivated and given its restricted range, these experiences are of high conservation importance and will be attempted to be reproduced in 2020. Spatalla parilis – Two batches of seed from different collections of this species were germinated with 5% and 25% germination rates achieved for each. The same method used to germinate Spatalla nubicola was also used to germinate this species. Seedling mortality rates have meant that only 3 plants are still alive, the best of which is shown in the photo on the right. Although this species has been cultivated before in Kirstenbosch by Louise Nurrish, her success was by striking cuttings of vegetative material collected in the wild. This is likely the first time that seeds of this species have been germinated ex-situ. Cultivation Protea aurea subsp. aurea In August 2019 Protea aurea subsp. aurea (BMR15032.02.03 - which was collected at 1424m on the southern slopes of Grootberg in Boosmansbos) became the first of our seed grown 2015 collections to flower - see photo below. The altitude of this seed collection is from the higher reaches of this species’ altitudinal range, with the upper quartile being at 1000m and the highest recorded plants being at 1620m. This plant is in a 20L terracotta pot and has flowered in 3 years and one month from germination (12/7/2016). Cuttings of this plant were taken in autumn 2020 in the hope that they may be trialled in the ground at some point. Protea pruinosa During 2019 one plants of this species was potted up into a 4L terracotta pot and another was planted out in the trial bed. The plant in the pot is growing very strongly (see photo on right) but the plant in the ground is now dead. The reasons for this are unclear but more plants are available in 1L pots to both pot up and plant out. Protea cryophylla Four plants of this species are at the nursery. One is in the ground, having survived its first winter in a trial bed. Another is in a 10L terracotta pot that was left outside all winter, to no ill affect. The remaining two are in 1L and 2L pots respectively and are on a bench in the greenhouse. To minimise root disturbance and mimic its wild habitat of cracked rocky ground, the pot-in-a-pot-in-a- pot method is being trialled with some of these plants.