Cranberries are not only trendy because of their he althy fruit. They are also an eye-catcher as ground cover. We show how best to plant them.
While it has been grown commercially in the US and Canada for some time, the cranberry (Vaccinium macrocarpon) has only recently gained prominence in Europe. No wonder - after all, it tastes very similar to the local lingonberry (Vaccinium vitis-idaea). The cultivation conditions are also similar, after all the cranberry belongs to the same plant genus as the cultivated blueberry (Vaccinium corymbosum) and the lingonberry. We tell you how you can imitate the conditions prevailing in the forest in your garden and plant cranberries yourself.
Cranberries: origin and description
The cranberries, which originate in north-eastern North America, owe their name to the shape of the flower, which is reminiscent of a crane (crane). Cranberries form tendrils and only grow to about 25 cm in height. For this reason, they are often used as ground cover. As such, they make a great impression with their beautiful flowers and red, very he althy berries. Cranberries form a dense root system shallow underground. The leaves of the cranberry plant are evergreen, somewhat leathery and waxy to the touch, and only regrow every few years. In autumn, leaf and flower buds develop on the side shoots for the next year.
Cranberry Varieties: An Overview
There are numerous cranberry varieties to choose from in garden shops and online nurseries. We have had good experiences with the following three varieties and are therefore happy to recommend them:
'Early Black': Early ripening variety with dark red to slightly blackish berries; very aromatic, medium-sized fruits; very frost hardy
'Stevens': Fast-growing and very productive variety; recommended for drier soils and harsher climates
'Bergman': High-yielding variety with medium-sized, dark red fruits; grows flat and forms a lot of foliage - therefore ideal as groundcover
Planting Cranberries: Site Conditions
As their membership in the heather family (Ericaceae) already suggests, cranberries prefer natural heathlands. Sand and peat soils are among the original habitats of the cranberry, although it does not tolerate waterlogging or drought for long periods.
Cranberries like sunny to slightly shady locations with a soil pH of 5. Normally only forest soils have such a low pH. But there are some tricks you can use to acidify the garden soil a bit, i.e. to lower the pH from a normal 6-7 to 5. In very calcareous soil with a pH value of 8 or higher, however, these tricks do not work in the long term. After a while, the soil levels out the acidification and is then no longer suitable for cranberries under these conditions. Therefore, in garden soils with a pH of 7.5 or higher, it may be more beneficial to plant cranberries in planters or pots with acidic rhododendron soil.
Tip: In order to create good site conditions for your cranberry, you can use high-quality organic soil such as our Plantura organic universal soil with sand and bark humus, spruce needles, grape pomace or similar material mix.
How do you find out the pH of your soil?
- You can buy so-called pH meters including a certain substance in gardening shops. This substance is mixed with a little soil and causes a chemical reaction. You can then use a color chart to read the pH of the tested soil.
- Alternatively, you can buy small amounts of 10% hydrochloric acid in pharmacies. If this is dripped onto a piece of soil with a pipette, a chemical reaction also occurs. The higher the lime content of the soil, i.e. also the pH value, the more it bubbles. If a lot of bubbles form, the soil is not suitable for cranberries. If none form at all, it is very well suited. Slight frothing reveals that planting cranberries is possible with proper soil preparation.
In order to obtain a meaningful result and to rule out application errors, we recommend that you carry out both tests in two to three places on the area planned for the cranberries.
The relatively hardy cranberries are usually not at risk of frost. The plants are only sensitive to early frosts in autumn or late frosts during budding and are therefore happy to have warm protection from fleece, rips or similar materials.
Planting Cranberries: Instructions
Cranberries are planted in spring from March to May or in autumn from September to mid-October. Before planting, however, the soil must first be prepared. The soil of the entire area to be planted is dug about 15 to 20 cm deep. This soil can then be used for other beds such as raised beds. It must be replaced for the reason that it is not acidic enough. This 15 to 20 cm deep layer of soil is now filled with a mixture of sand, rotted bark mulch or bark humus, rotted compost, needle litter and acidic rhododendron soil. Sand is mixed in at a proportion of around 10 percent. Now it's time to plant. A planting distance of 20 to 30 cm has proven effective for rapid ground cover that suppresses weeds. Cranberries form many runners and spread well. This is another reason why they are well suited as ground cover.
After planting, you should water the young cranberry plants generously. Then cover the ground with bark mulch. The soil is also acidified by the decomposition of the bark mulch. However, you should not use bark mulch too excessively, since the bacteria that break down the bark mulch fix nitrogen. In the worst case, this can lead to a less than optimal supply of nitrogen to the cranberry.
Harvesting and storing cranberries
The cherry-red berries, which are about 1 to 2.5 cm in size, are harvested from the beginning of September to the end of October. If you don't harvest the cranberries, they will grace the plant well into spring. But that would actually be a shame, after all, cranberries contain a relatively large amount of iodine and many vitamins. The berries are fresh and can be stored in the refrigerator for up to two months, but are not suitable for consumption in large quantities. Thanks to their natural preservatives (e.g. benzoic acid), cranberries can be processed very well without sugar to make juices, compotes, jams or similar.
