proteas With Altitude Annual Report January – December 2020 Robbie Blackhall-Miles and Ben Ram Abstract This report aims to show how the ‘proteas With Altitude’ project progressed during 2020, documenting the experiences of the project over the 12-month period. It provided an opportunity to review the ongoing process of managing 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, based in the UK, studying the horticulture of a wide range of cool growing montain Proteaceae species. 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, with plants and cuttings of some species being imported under phytosanitary certificate. A full report detailing progress up to the beginning of 2020 can be found in the 2016, 2017, 2018 and 2019 annual reports. This report will discuss the period between January 2020 and December 2020. Nursery Infrastructure This year, a hose adapter for the water storage tank was purchased, allowing plants to be watered with rainwater by hose rather than by watering can. This has reduced the amount of time it takes to water plants with rainwater. The tank got low occasionally but never ran out. A new battery and thermometer were purchased for the weather station, allowing us to record weather once more. There is now a mobile phone connected to the weather station, enabling weather at the nursery to be monitored remotely by streaming data to the internet. Germination Efforts to germinate seed in 2020 were concentrated on species which have previously proven difficult. This meant that of the 32 seed batches sown, only 9 batches had any germination. All germination happened between 17 and 41 days from sowing with seeds from each batch germinating over a period of 7 to 18 days. Leucadendron dregei had a 50% germination rate but then 40% mortality rate. Two plants of Spatalla parilis germinated, both however both died soon after. Any germination for this species is useful as it implies that the germination method must work to some extent. Aulax pallasia also had germination, but both plants have unfortunately now died. Protea recondita had a 40% germination rate. Germination was also achieved for Protea humiflora and Protea subulifolia. This brings the number of species of Proteaceae from South Africa covered by this project to 58. Propagation by Cuttings During 2019 some success was had with production of plants from cuttings. Semi ripe plant material was treated with a rooting hormone and placed in pots of free draining protea compost. Successful rooting took place in a comparatively short period. Literature regarding the propagation of Proteaceae by cuttings suggests gentle bottom heat, so the decision was made to invest in a thermostat-controlled heat mat, covering just over a meter length of the nursery bench. Cuttings were taken from a range of species, giving priority to plants for which a back-up was needed due to low numbers in the collection and low likelihood of producing more from seed. Success with this has been limited, with a lack of suitable drainage has proving to be a problem that we had not anticipated. This led to compost retaining water subsequently rotting many of the cuttings. It also led to a lack of callus formation and thus minimal root production. Some cuttings remained alive for most of the year, surviving only on a callus. Cultivation FossilPlants is registered with the UK’s Animal and Plant Health Agency (APHA) and undergoes regular inspections for notifiable pests and diseases. The nursery is split into two areas with one area having a Polytunnel for receipt of new plant material. New plants are held here for a minimum of 3 months before they are moved into the main nursery area or into the garden. The main nursery area is fenced from the reception area and has increased plant health precautions including an entrance Chloroxylenol foot bath and all floor areas covered with a membrane that can be regularly disinfected. An integrated pest and disease management system is used with prevention and biological pest control the preferred choice for any insect pests and disease. Chemical pest control is only used when other controls have repeatedly failed and is undertaken with the health of the plants and the wider biodiversity of the nursery site in mind. Few pests have had significant impact for the proteas With Altitude project, with the most significant to date being Mealybug infestation and tortrix moth caterpillar. Other damaging pests have been Fungus gnats which particularly effect seedlings and mice which nibble emerging flowers. The control of pests such as Mealybug, Tortrix moth caterpillar, Fungus gnats (sciarid fly) and mice has had varying levels of success. Tortrix moth has proven to be a pest for both plants outside and in our polytunnels. It has a particularly negative impact on Leucadendron but affects all Proteaceae species. The caterpillars use silk to bind leaves together at the growing tip of plants while they feed on the growing tip itself. This can be very damaging, but we have found that this problem is best controlled by picking off individual caterpillars by hand once noticed. Fungus gnats eat plant roots, usually in wet compost, often when seedlings have been potted up. This can be avoided by having a free draining mix and placing pots on a bench that is free draining. This can also be a problem while rooting cuttings, particularly if a heat mat is used as this often impedes drainage. Using the insectivorous plant Pinguicula ‘Tina’ has proven the most effective way of controlling this pest. It is important to note that Pinguicula ‘Tina’ is a hybrid between two Mexican Pinguicula species and as such prefers to be kept dryer than most other carnivorous plants. We have also had success with Drosera capensis for controlling fungus gnats but not to the same extent as with the Pinguicula. The first signs of Mealybug are white cottony masses (egg masses) in leaf axils and subsequently the growth of sooty moulds appear due to the build-up of excreted honey dew on the leaves. Mealybug infestations seem to start by affecting plants in the polytunnels but will remain on the plant after an extended period outside. This is even the case on plants that have been outside continuously for over 12 months with rain and frost. The species of mealybug that affects the Proteaceae at the nursery has not yet been investigated. Picking off the mealybugs by hand is a time consuming, laborious, and painstaking work and is often an ineffective method of control in the long term but will reduce pest numbers temporarily. Releasing the larvae of the ladybird Cryptolaemus montrouzieri helps to control mealybug numbers through predation during the very short warmest part of high summer as they need temperatures of over 18C to be effective. We have found that Lacewing larvae, however, are effective predators of mealybug when the temperature is over 15C, allowing their use as a predator for a greater portion of the summer. Many potted plants are housed in the polytunnel from late November to mid-April. During these cooler months as part of our integrated pest management strategy, spraying all plants in the polytunnel with the systemic neonicotinoid Bug clear ultra (active ingredient Acetamiprid), can help control severe infestations of Mealybug. This is done once at the beginning of this period, while the temperature is still warm enough for Mealybug to be active, yet late enough in the season to reduce exposure of pollinating insects and breeding birds. Plants in the polytunnel are then sprayed again when Mealybug activity is noticed due to increased temperatures towards the end of this period. Spraying is conducted by closing the polytunnel completely for 24 hours during and after spraying. To minimise the effect of this pesticide on other insects, spraying does not happen if plants are flowering and will not happen in the 3 weeks prior to plants being taking out of the polytunnel. The impact of this spraying reduces mealy bug infestation allowing mealy bug control by biological means through the rest of the year. Mice are attracted to rodent pollinated proteas, such as Protea cordata and P. venusta, however rather than pollinate them will often chew on the flowers and nearby shoots. This has also been noticed on some species of Erica. Mouse control is undertaken as and when required. Traps are set near to plants liable to damage or once first signs of chewing are noticed. Traps are bated with peanut butter and in this way the offending mouse is usually caught. Mouse control is only undertaken when necessary. When a plant dies in a pot it is our practice to investigate the rootzone for signs which might indicate the reason for death. Often an Earth Worm is found in such pots. Earth worms are rarely found in the compost of healthy plants or when a plant is potted up. Earthworms are known to eat plant roots when in pots and thus there may be reason to believe that earthworms have been a significant pest for us, especially for younger plants. Given that young plants are kept on benches the question of how they find their way into the pots remains unanswered.