Rhododendrons for non-acid soils

Val Bradley

If there’s one shrub that puts on great show in late spring, it’s the Rhododendron with its clusters of bell-shaped flowers in white and shades of red, pink, yellow or purple. As members of the acid-loving Ericaceae family, though, they won’t grow in every garden.They need specific soil conditions and to grow them in a non-acidic garden means keeping them in a container or creating (and maintaining) a special bed.

Or it did. If you want to grow a Rhododendron in a less-than-ideal soil, look out for the word INKARHO on the label. This indicates that the plant has been grafted onto a special lime-tolerant rootstock that allows it to tolerate any acid to neutral soil.

It was discovered in northern Germany, when a keen-eyed grower noticed a wild rhododendron growing in a lime quarry. Cultivated, developed and tested by nurseries in the area over 20 years, it is grown under licence and used on various varieties of Rhododendrons in soils up to pH 7.5.

They need more feeding than an average Rhododendron in order to stay healthy, but will reward you with a magnificent display.

If you have fallen victim to the dreaded box blight or box caterpillar and are looking for an alternative plant, the INKARHO rootstock has also been used for the Bloombux series of plants. These small evergreen Rhododendrons resemble box (Buxus) with the bonus of a flush of attractive pink or magenta flowers.

To see a wide range of INKARHO varieties, Click Here

This story was published on: 25/03/2026

Image attribution: Val Bradley

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