OUR ORCHARDS
Our olive orchards, totaling 135ha, were planted primarily between 2006 and 2009, with 20ha added between 2021 and 2023 and a further 5ha in 2024. Our orchards comprise of 77 000 trees, situated primarily on Groot Kruis at the top of the farm and Oudemuragie lower down in the valley.
The initial cultivars: Frantoio (and its clone Favalosa), Coratina and Lucina are a blend from Tuscany in Italy. Since then the farm has experimented with several cultivars from Spain, Israel, Greece and Tunisia in an effort to find trees that best adapt to our climate.
Although the farm has both Kalamata (black) and Manzilla (green) table olive cultivars, its primarily function is to produce premium quality Olive Oils, hence the selected cultivars are “oil” cultivars. Healthy trees have adequate nutrients and water and simply look heathy. At De Rustica you can see the colour and vitality of our trees and this is in no small part the result of our sustainable orchard management and soil health.
ORCHARD MANAGEMENT
Throughout the year our team works on the health and sustainability of our olive orchards. We aim to augment and restore the cycles of nature – the energy cycle, the carbon cycle, the microbial cycle, the mineral cycle and the water cycle.
We allow the space between the rows to grow diverse herbaceous plant cover which we mow, and distribute between the trees. We chip and return all pruning material between the trees (the bankie) and augment this with pomace and sheep manure, aiming to evolve a deep layer of plant biomass to cover the earth, limit water evaporation and stimulate a healthy microbiology in the soil.
Pests and diseases are closely monitored and controlled. De Rustica’s dry desert conditions limit fungal diseases and our isolation limits visiting pests. We tend to avoid treating pests and diseases in a “blanket’ fashion rather targeting specific problem areas to build systemic resistance.
We focus on ensuring that our trees are well irrigated and pruned to maximise health and yield. We monitor soil moisture weekly and if needed use hand auger samples to refine and optimise our water use.
Winter: Dormancy
Olive trees require a cold period to go into dormancy and rest. Different cultivars require more or less “Cold Units” during this period. Cold Units are average daily temperatures below 12 degrees C and these units are preferably continuous varying from about 250-650.
Our dormancy period normally starts in mid-July and goes to the end of August. Frost assists and we believe that it’s the temperature of the ground, and one metre above it that is critical.
Spring : Buds, blossoms and fruit set
Spring begins with the development of the buds in early September. The blossom opens from mid-September to mid -October. In a good year the trees are literally covered with the tiny yellow-white blossoms and a carpet of blossoms fall below the trees.
Olive blossom is wind-pollinated, ideally in temperate conditions. Hot dry strong ‘berg’ winds can damage pollination. Whilst certain cultivars are self-pollinating, most benefit from some degree of cross-pollination. We pay attention to this characteristic, and prevailing wind directions, when laying out orchards and selecting the cultivar mix. Ultimately only about 4-6% of the blossom will pollinate which is enough for a good yield.
Interestingly the blossoming period varies greatly by cultivar. Some like our favourite, Coratina, has a long blossoming period of up to 10 weeks. This builds in redundancy insurance as poor conditions for a fortnight or so can be “caught up” with pollination success at other more benign times in the period of blossoming. Others, like the FS17 /Favalosa cultivar have a short and intense blossom and pollination period, of about two weeks. We have to hope that conditions are ideal during this time.
Pollination leads on to a ‘fruit set’ which is mission critical and can mis-fire resulting in what is called ‘shot-berry’ (when the fruit does not develop and grow). There can be many reasons for this, but weather at the time of pollination and the health of the tree play key roles.
Interesting Fact – Unlike other fruit and nut trees Olive trees put their survival above yield and reproduction. If an Olive tree is stressed it discards its olive fruit and stops the fruit bearing cycle until its health is restored. Other fruit and nut trees put an emphasis on reproduction (thus bearing more fruit) during stressed times and sacrifice longer term health. Indeed it is possible to stress deciduous fruit trees without damaging them, to stimulate yield.
Summer : Maturing and ripening
De Rustica’s altitude and mountain slopes mitigate the extreme heat of the Klein Karoo summer so that temperatures in excess of 40 degrees are unusual at the farm.
We pay close attention to our weather conditions to ensure that any unusually hot or windy periods are matched with higher water irrigation volumes. Our Orchards are irrigated throughout the growing season, using fresh mountain water, gravity fed from our catchment dams to our double drip system beneath the trees. The olives mature during the long hot summer months from November to March and eventually change colour, signalling the onset of the harvest, (normally in late March).
Autumn : Harvest and pruning
Our harvest starts in late March and finishes between early June and late July depending on harvest size and weather days that prevent picking. All picking is done by hand, using combs that gently pull the olives off the trees and onto shade cloth below.
The olives are collected, crated and transported to our Processing plant every day. We are able to process 15-30 tonnes a day. Care is taken to prevent sun damage and control the temperature of the fruit en-route to the press. Post harvest pruning is essential for the success of the next year’s crop. Pruning is done by a specialist team who follow the harvest teams as soon as they have completed their work in the orchards.
Interestingly in the 2024 harvest throughout South Africa, oil extraction yields were markedly lower than usual. This was not due to a lack of pruning, but rather, it is thought, to a number of unusually hot periods that retarded oil development in the olives.