Blooming – the blooming period occurs from the end of May to the second half of June. Large flowers of light purple color, with characteristic yellow-brownish-red to olive-yellow color with a speckled pattern. The petals have slightly frayed edges, are quite large, and measure from 5 to 7.5 cm in diameter. The stamens are the same color as the petals, and the style is darker. The flowers are gathered into dense (13 to 15 cm in diameter) spherical inflorescences. The shrub's leaves are elongated elliptical, dark green, slightly shiny, 10-13 cm long, and 3.5-4.5 cm wide. The leaves stay on the branches for many years.

Growing conditions and requirements – Catawbiense Grandiflorum requires semi-shaded or shaded positions with high air humidity. It is important that planting sites are sheltered from the wind. It prefers acidic, moist, and humus-rich soils.

Care – for planting, choose primarily young, lush, and densely foliaged shrubs. The best planting time is April or the turn of September and October.
Like all rhododendrons, the Catawbiense Grandiflorum variety has very delicate roots and a small, compact root ball. Therefore, it can be freely transplanted even during the flowering phase.
The most important aspects of growing these shrubs are mulching and weeding. A thick layer of spread bark, acidic humus, or leaf soil will protect against weed development. Remove any weeds manually to avoid damaging the shrub's shallow roots. Rhododendrons require constant soil moisture, so regular watering is important. The highest demand occurs during the blooming and new leaf development periods.
During the growing season, evening misting of the leaves is beneficial for the plant’s condition.
Catawbiense Grandiflorum is a variety known for its high frost resistance. It can withstand temperatures as low as -30°C. However, young shrubs need winter protection.
To give the shrubs a decorative appearance, you can use shaping cuts. In this case, cut the branches at the growth boundary, at the points where the characteristic swellings, known as rings, occur. Thanks to strong growth and compact habit, even older shrubs are capable of rapid regeneration after pruning.

Application – Due to its aesthetic value and low requirements, the rhododendron Catawbiense Grandiflorum is ideal for naturalistic plantings in parks and gardens.
This variety’s shrub can be planted as a single decorative feature, near other, preferably smaller plants. It also works well as an original hedge. Due to its large size, shrubs should be planted at greater distances.