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THE IMPORTANCE OF PRUNING SEA BUCKTHORN.

We began researching the many sea buckthorn cultivars available to us from our local area and from around the world in 2009.  While studying how to best grow this shrub as a commercial crop we had the incredible opportunity to learn from the president of the european sea buckthorn association. An agronomist with a longtime focus on sea buckthorn, he has developed many of today’s most recognized cultivars. 

After years of applying his teachings, we have develop into a wholesale company and are proud to offer some of the most palatable varieties of sea buckthorn shrubs to nurseries and homestead growers. Our homestead customers have come to rely on us to guide them in the proper growing techniques to achieve a successful and productive plantation. One of the most often asked about topics is on the techniques of pruning and harvesting sea buckthorn. 

Pruning Sea buckthorn for max health and yield.

There are several benefits to maintaining a well pruned Sea buckthorn orchard and how your plants will respond to regular pruning depends greatly on the species, subspecies and variety. The main objectives for pruning sea buckthorn is to maintain proper size, shape and architecture in order to facilitate fruit harvest, to maximize light exposure for better growth of fruit and to produce & maintain the optimum amount of new fruit bearing branches. Regular pruning also keeps your plantation healthy and vigorous by eliminating dead or broken branches.

Maintenance pruning can start the first year shrubs are planted and should be practiced with the principle that all branches will be replaced in a specific order over 3-4 years. Using a combination of heading back, thinning and shortening cuts, it is most advisable to prune in late winter or early spring, before the buds break. This will stimulate vegetative growth, so be mindful in your cuts, as over crowding of branches is a leading factor for low fruit yield due in part to low amounts of light penetrating the inner branches. It is better to make a few important cuts then many small cuts.
A trimmed branch should be smooth and at an angle to encourage the healing process and to avoid disease. Properly maintained pruning secateurs and saws are a must for an efficient and clean trim. For best phytosanitary protocols, tools should be cleaned after pruning each plant and sharpened regularly.

The general way of harvesting sea buckthorn berries is by strategically cutting back its fruit bearing branches from year to year down to the optimum height for manual harvest, which is between 1.5 – 2.5m (5-8′). Freezing the fruit immediately while still on the branch. Then, once the fruit are frozen a simple vibration will make the berries easily fall from the branch. Commercial separating equipment is available but this equipment can also be crafted easily enough. In Germany, whole plantations are harvested by “total cut” of the bush, using specifically engineered harvesting machinery. These machines cleverly cut down on time and long term costs to harvest, but the down fall is that most modern Sea buckthorn cultivars do not endure over the long term under this extreme cutting method. Adding that it delays subsequent harvests, this is not the most commonly used method of harvest/pruning, as it necessitates very large plantations that can be alternated to compensate for the crop loss.

THE IMPORTANCE OF PRUNING SEA BUCKTHORN. -total cut harvest
Sea buckthorn shrubs are harvested with specialized machinery in Germany.

 

Baltic growers most commonly use the “lower cut” or Modified Leader Method of harvesting Sea buckthorn. With this method, the plants are headed at the height of 60 cm (~2′) after the first year of planting, which leads to the formation of several upright and narrow angled branches. The top shoot becomes the central leader during the first season of growth. At the end of the second year’s growth, all branches shorter than 30cm (12″) above ground should be cut back. All other branches should be cut back only to maintain a taller central leader. During harvest, unimportant and weak branches are chosen first. They are located in the lower and inner parts of the tree. Then branches larger than 50% of the leader diameter are removed. This eventually causes the formation of a single trunk, if the top shoots are untouched, sooner or later the main trunk will have to be cut down to form a new shrub with many branches.

THE IMPORTANCE OF PRUNING SEA BUCKTHORN. - modified leader
The modified leader method of harvesting eventually leaves a shrub in need of being cut back to form new branches.

This head cut is done in late winter or early spring, as plants recover best due to the carbohydrates still stored in the lower parts of the tree begin to circulate upward after breaking out of the winter dormancy period. If this is done in September, as in the “total cut” method, these essential nutrients are cut down along with the top branches.  The principal disadvantage of the lower cut method, is that the radical cut of the main trunk causes two empty years before the tree is replenished to full harvest for another 4yrs.

 

 

 

 

 

THE IMPORTANCE OF PRUNING SEA BUCKTHORN. - vertical split
Drawing of vertical split method.

In an attempt to improve on the previous method’s downfall, pruning was adapted to create two equal parts within the tree with one year age difference between the sections. This is called the Vertical Split Method (see image for visual description of this method). The vertical split has the advantage of less maintenance pruning, better light penetration for better fruit production, the tree naturally retains the best height for manual harvest. All branches on the harvest side must be cut back, this causes every third year to be non productive when applying this method. The bush is gradually rejuvenated avoiding a long interruption in harvest years. However, this method can only be used in well planned and maintained orchards, because when the plant is not getting enough of what it needs like nutrients, water or sunlight, it will not regenerate the removed branch

 

Another method used by European growers is the Horizontal Split Method, which was created 10 years ago for hobby gardeners. In early spring annual shoots are bent down with the tops pegged to the ground. Fruits set on the bent branches while new vegetative shoots grow straight up from the upper points of the arch, this is caused by the accumulation of growth hormones due to positive geotropism. The lower parts of the branches are harvested in the fall while the new shoots remain untouched until the following spring when it will be their turn for the bending process. The horizontal split method is very gentle and makes for a beautiful looking plant. In certain cases it may increase yields, but more importantly, no barren years are experienced using the horizontal split. Nevertheless, this method is very labor intensive, and when there are a few hundred shrubs in a plantation, it can get costly in labor.

THE IMPORTANCE OF PRUNING SEA BUCKTHORN. - horizontal split
Examples of the horizontal split method of growing and harvest sea buckthorn.
THE IMPORTANCE OF PRUNING SEA BUCKTHORN. horizontal split
Horizontal split method. Area to cut.

 

Lastly, according to the book; Sea buckthorn (Hippophae Rhamnoïdes L.) : Production and Utilization, written by; Thomas S.C. Li and Thomas H. J. Beveridge, Sea buckthorn may perform well with the Open Center System. At planting, unbranched seedlings and rooted cuttings are pruned at approximately 60 cm (2′) and all buds within 30 cm (12″) from the ground are removed. Trees are trained to a multi leader system with major branches extending up and away from the trunk, giving a vase-shaped tree. At the end of the second year, all newly developed branches within 30 cm (12″) above ground are removed. Then remove the potential central lead branch, head back and thin all branches to maintain the desired height of <2m (6.5′). Pruning has to be performed every year to avoid problems as the trees become older. The fruiting zone moves higher and to the outside of the canopy and the tree gradually assumes an umbrella form. The book states that this system may produce shaded zones which may eventually cause poor fruit set. However, the important upper to middle section of the canopy should receive adequate sunlight and produce ample quantities of quality fruit. Minimizing shaded zones must be considered while pruning.

 

Bottom line, be mindful of the principals of pruning and harvesting Sea buckthorn. But remember that practice makes perfect and if you mess up, chances are you can make up for it later. A a healthy Sea buckthorn shrub will easily regenerate itself.

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Growing Sea Buckthorn -101

Seabuckthorn is a medium sized deciduous shrub with deep green, willow like leaves which shine with a silver glow in the sunlight. This beauty produces clusters of tiny orange berries which are highly desired for their nutrients. Growing sea buckthorn as a commercial crop can be a great way to add income to your farmstead, plus add a super nutritious food source for your chicken, cows, horses, and pigs. 

 

Growing Sea Buckthorn- frankia nodules
Frankia nodule growing on the roots of the sea buckthorn plant.

 This plant is at the top of many permaculture enthusiast’s list as best pick for symbiotic growing. The shrub’s extensive root system is capable of holding back the soil on fragile slopes. Often planted amongst other fruiting plants in commercial orchards for it’s nitrogen fixing actinomycetes (Frankia) which develop on the rhizomes. Seabuckthorn roots are also able to transform insoluble organic and mineral matter into more soluble forms when other soil conditions are favourable (Lu 1992). In the Canadian prairies the shrubs are used as wind breakers planted in hedgerows. 

 

Growing Sea Buckthorn.

Sea buckthorn grows well in many parts of North America but prospers best in climate zones 2-7, in areas receiving 400-600 mm of precipitation annually. The average mature height of most Seaberry cultivars is between 2-4m (6′-13′). Although, some subspecies can grow up to 18m (59′) H, while others grow no higher than 50cm (1.5′). Sunny spots are best as excessive shade will result in lowered fruit production and general growth. Being dioecious, there must be male plants within the same species present to pollinate the females in order to achieve fruit. Pollination happens when air temperatures are between 6°- 10° C (42°-50°F) and female flowers are receptive for about 10 days. Fruit ripen approximately 100 days after pollination. The seaberry plant will adapt well to many soil types (except clay) and is happiest in a soil between ph 6-8. A healthy seabuckthorn plant won’t need nitrogen to thrive but will respond to phosphorus and will benefit from regular winter top dressing. We recommend a good quality marine compost but any manure will do. Professionals studying production standards in sea buckthorn reported that foliar sprays with micronutrients, Cu, Mo, Mn, I, B, Co and Zn, increased fruit weight by up to 34.5% (Mishulina 1976). Also, egular watering during hot dry months (July – August) also helps to improve yields substantially.

Growing Sea Buckthorn - sea buckthorn with fruit on branch
Mature fruiting sea buckthorn bush ready for harvest. Cultivar: Sunny

There are many propagated cultivars on the market. Most we’re developed in Russia, China, Europe and Canada. Many varieties have been developed to have fewer thorns and sweeter fruits. It should be noted that no sea buckthorn berries can be considered truly sweet. The most widely grown cultivar in central and eastern Europe is named Sunny (Botaniceskaya). This cultivar was initially developed in Russia but has travelled throughout the years across Europe and into North America, as it is a favorite for it’s large, juicy berries with a lightly acidic taste.

 

Growing sea buckthorn from seed can be an affordable way to build a sea buckthorn grove but one must keep in mind a few consequences when considering this option. Wild sea buckthorn is naturally prone to large thorns, agressive suckering and generally bitter/sour fruits. When planting from seed, you never know what you are going to get as a result. You may end up with a thorny bush or extremely bitter tasting berries.

 

Some uncertainties as to the invasive nature of sea buckthorn have been called into question over the years. Dr. A Bruvelis, a long time seabuckthorn propagation expert in Europe, states,. “There are some officials (mainly in Great Britain) who account sea buckthorn as an invasive species. [Sbt] has not generally been considered to be a desirable feature on sand dunes in Eastern England and South Scotland because of forming of dense thorny thickets in recreational areas. [Sbt] spread around by root suckers and very, very rarely by seeds. We should always keep in mind that they talk about wild stands exclusively on sand dunes, where [sbt] is able to compete with other species due to humble growing requirements. Considering Seabuckthorn spreads primarily through root suckers, which might sprout up neighbouring plots around small private gardens and urban backyards. In commercial plantations root suckers are mowed along with grass. Old abandoned plantations can become like impenetrable jungles. Excellent place for wildlife.”

Sea buckthorn is not on the invasive species lists of North America, -but one must be mindful of the above information when choosing where to plant their shrubs. Growing sea buckthorn in sandy areas will grow up fast with sucker plants and horizontal rhizomes can sprout far if not mowed regularly. Severing surface roots 40cm (16″) around the base of the shrub and removing roots down to 20cm (8”) beneath the surface of the soil can significantly help reduce undesired spreading.

 

Growing Sea Buckthorn - sea buckthorn root system diagram
Eliminating surface roots will greatly reduce undesirable suckering.