Understanding the Cloudberry Plant
The cloudberry (Rubus chamaemorus) is a rhizomatous herbaceous perennial plant in the rose family. Native to the cool temperate and subarctic regions of the Northern Hemisphere, especially Scandinavia and RussiaLink Text, cloudberry grows in bogs, wet meadows and tundra.
With yellow flowers and an amber-colored fruit, the cloudberry plant has a creeping habit. Its leaves have five leaflets and are dark green on top and light green underneath. The flowers usually appear in May or June and the fruit ripens in late July and August. The ripe cloudberry fruit looks like an amber-colored raspberry and has a distinctive tart taste.
Cloudberries are a circumpolar species that favors peaty soils and grows best in areas with long daylight hours in the summer as well as cold winters. Preferring damp, acidic soil with lots of organic matter, cloudberries often grow in isolated patches across bog and tundra. The plant spreads through underground stems called rhizomes and forms dense mats. Cloudberries have been used in traditional medicine and the fruit is a source of benzoic acid, quercetin and vitamin C.
Choosing the Right Soil for Cloudberry
Cloudberries have very specific soil requirements to thrive. The ideal soil for cloudberries is acidic (pH 3.5-5), high in organic matter, and continuously damp but not soggy. Some key factors to consider when preparing soil for cloudberries:
Acidity: Cloudberries prefer acidic soil, so the pH should be between 3.5 and 5. Have your soil tested and amend as needed with elemental sulfur, peat moss or pine needles to lower the pH.
Moisture: Cloudberry plants require damp soil, especially for the first couple years of growth. The top 6 to 8 inches of soil should remain moist but not waterlogged. Using a mulch like peat moss helps retain moisture in the soil.
** organic matter**: Cloudberry plants need soil high in organic matter such as peat moss, compost, rotted manure or leaf mold. Work 2 to 3 inches of organic matter into the top 6 to 8 inches of soil before planting.
Drainage: While cloudberries need moist soil, they do not tolerate sitting in water. The soil must drain well and not become waterlogged. Adding perlite or sand to heavier clay soils helps improve drainage.
Nutrients: Cloudberries have low nutrient needs, but the soil should be naturally fertile or supplemented. A low dose, balanced, slow-release fertilizer with equal parts nitrogen, phosphorus and potassium, such as 5-5-5, can be applied at planting and again in early summer.
Here is a summary of the ideal soil properties for cloudberries:
|Acidity||pH 3.5-5 (strongly acidic to slightly acidic)|
|Moisture||Damp but not soggy, top 6-8 inches moist|
|Organic Matter||2-3 inches of peat moss, compost, etc. worked into top 6-8 inches of soil|
|Drainage||Well-drained, permeable to water but does not become waterlogged|
|Nutrients||Low needs, balanced slow-release fertilizer (e.g. 5-5-5) at planting and in early summer|
Spending time preparing the proper soil will pay off with healthy, productive cloudberry plants. Reviewing soil requirements and adjusting factors such as pH, moisture and nutrients will help you achieve the ideal conditions for your cloudberry patch.
Planting and Watering Cloudberry
Once you have prepared the ideal soil for cloudberries, it is time to plant and establish them in your garden. Here are some tips for planting and watering cloudberries:
Planting: Cloudberries can be propagated from rhizome cuttings, root cuttings or layering. Plant in the spring once the threat of freezing temperatures has passed but while the soil is still cool. Space the plants 3 to 6 feet apart. Bury the roots just deep enough to cover them with about an inch of soil.
Watering: Cloudberries require damp soil, especially for the first couple years as they establish themselves. Water regularly to keep the top 6 to 8 inches of soil consistently moist. Aim for about 1 to 2 inches of water per week. Check the moisture level of the soil before watering by pushing your finger into the ground. Only water when the top few inches become dry.
Mulching: Apply 2 to 3 inches of mulch such as pine needles, shredded leaves or peat moss around the base of plants after planting and watering them in. The mulch will help retain moisture in the soil and prevent weeds. Replenish the mulch as needed to maintain a 2 to 3 inch depth.
Frost protection: Cloudberry flowers and fruits are sensitive to frost. Cover plants with frost protection cloth or fleece if frost is forecast during flowering and fruiting. Remove the covering once the risk of frost has passed.
Fertilizing: Go light on fertilizer, especially for first year plants. Too much nitrogen can reduce yield. Apply a balanced, low-dose fertilizer (such as 5-5-5) once in early summer, following the directions on the product packaging for amount.
Proper planting, watering and aftercare is crucial for establishing a new cloudberry patch. With the right soil in place and attention to moisture, mulch, frost protection and light feeding, your cloudberries should thrive and produce berries within a couple years. Be patient through the establishment period – cloudberries can take time to become established but with the right conditions will produce for 15-20 years or more.
Fertilizing and Pruning Cloudberry
Fertilizing: Cloudberries have low nutrient requirements and too much fertilizer can reduce berry yield, so fertilize lightly. For established plants, apply a balanced, low-dose fertilizer once in early summer, following the directions on the product packaging for amount. A fertilizer with equal parts nitrogen, phosphorus and potassium, such as 5-5-5 or 10-10-10 works well for cloudberries. Reduce the amount to one-half to one-quarter the recommended rate. First year plants often do not need additional fertilizer if they were planted in soil amended with compost or other organic matter.
Too much nitrogen can reduce cloudberry yield, so do not apply nitrogen-heavy fertilizer. Manure, compost and organic-based fertilizers are good options for cloudberries. As an alternative, try an organic liquid seaweed or fish fertilizer. Apply once in early summer following the directions on the product packaging. Use organic or non-chlorinated water if possible.
Pruning: The most important pruning for cloudberries is removing flower and fruit stems after the berries have been harvested. Cut the stems down to the base. This will promote new shoot and flower bud formation for the next growing season.
Other than that, cloudberries require little pruning. You may remove any damaged or diseased stems as well as any stems with fewer than 6 leaves. Pruning cloudberries in the fall or winter while the plants are dormant can stimulate the formation of new shoots which may reduce berry production for the next year. Therefore, restrict any major pruning to removal of damaged stems and spent flower/fruit stems after harvesting.
With their low maintenance requirements, cloudberries do not need regular pruning and shaping like many other berry plants. However, providing light annual fertilizer and ensuring spent stems are removed after harvest will keep your cloudberry plants productive and healthy for many years. Keep pruning to a minimum and avoid heavy pruning whenever possible to allow your cloudberries to produce an abundant berry crop each year.
Common Cloudberry Pests and Diseases
While relatively low-maintenance, cloudberries can still face potential pest and disease problems. Here are some of the common issues to watch for:
Aphids: Aphids are small, sucking insects that feed on cloudberry leaves and buds. They can spread virus diseases and weaken plants. Monitor for aphids regularly and spray them off with a strong jet of water or apply insecticidal soap or neem oil.
Scale: Scale are small, hard or soft bumps that suck sap from leaves and stems. They can be scraped off with a fingernail or scrub brush. Apply horticultural oil or insecticidal spray in early summer to kill scale.
Leafhoppers:Wedge-shaped leafhoppers suck sap from leaves and can spread disease. They fly or hop quickly when disturbed. Apply diatomaceous earth or sticky traps to monitor and control leafhoppers.
** Fungal leaf spot**: Circular or angular spots on leaves, often with a yellow halo. Can be managed by pruning infected leaves, improving airflow and sanitation, and applying a copper or sulfur fungicide.
Botrytis blossom blast: Gray, fuzzy fungal infection of flowers, especially in cool, damp weather. Remove infected blossoms and apply fungicide with chlorothalonil or copper to protect healthy flowers. Improve airflow and drainage.
Root rots: Soil inhabiting fungi can infect roots, especially in poorly drained soil. Plants may be stunted, produce little growth and berry yield decreases over time. Improve drainage and soil conditions. As a last resort, you can try applying a fungicidal drench in early spring before growth starts.
** Viruses**: Spread to leaves by aphids and other sucking insects resulting in mosaic patterns, leaf distortion or ringspots. Control the insects to prevent virus spread. Destroy badly infected plants.
Prevention of common pests and diseases involves good cultural practices: selecting a proper site, improving air circulation, drainage and sanitation, and monitoring plants regularly for any issues. Apply organic sprays only when necessary and according to instructions. Harsh chemicals should be avoided. With vigilance and care, your cloudberries should remain relatively problem-free.