Garden Plant of the Month for July: Potted summer bulbs: Calla, Lily and Star of Bethlehem

Plante de jardin du mois de juillet : Bulbes d’été en pot : le Calla, le lis et l’ornithogale

Colourful, impressive, summery bulbs 

Most people are familiar with spring-flowering bulbs but there are also a various range of bulbs sold in pots in the summer months that can bring colour and atmosphere to the patio. We have selected three summer-flowering potted bulbs as the Garden Plant of the Month for July: the Calla, the Lily and the Star of Bethlehem. Varied, colourful and impressive, both on their own and combined together or with other garden plants.

Potted summer bulbs: Calla, Lily and Star of Bethlehem
Zantedeschia is often known as the Calla or Arum Lily. In the past, we were only really familiar with the flowers of the white Zantedeschia aethiopica – it has large white calyxes and can grow quite big in the garden. There are now more compact varieties, in many different colours from white to orange and dark purple to yellow. The flowers are smaller, the plants also have attractive markings on the leaves in the form of silver spots.

Potted Lilies are all hybrids – many original species originate from Japan, China and Korea. The name LA (Longiflorum x Asiatic hybrids) is an old Latin plant name for the Lily. The plant is characterised by the many buds on the stem and the leaf that extends the full length of the stem. The larger the bulb that is used, the more buds there will be on the stem. The most common potted Lilies have large flowers with a strong scent, and the LA Group usually comes in pastel shades. The range of colours varies from yellow, orange and red through to pink and white. Many bicoloured lilies also have flowers with an extra spot in the Calix.

Ornithogalum, as the Star of Bethlehem is officially known, grows from beautiful leaf rosettes from which a leafless stem emerges with the flower on the end. The name Ornithogalum derives from an old Greek plant name which means ‘bird milk’ (‘ornithos’ = bird, ‘gala’ = milk). There are three most common species. O. Saundersiae has long stems over a metre in length bearing a composite white flower. Every separate flower has an eye-catching black dot at its heart. O. dubium is much shorter, often just 10 to 30 centimetres and is available in orange and yellow. O. thyrsoides has white composite flowers in the shape of plumes.

Caring for Calla, Lily and Star of Bethlehem
The summer-flowering bulbs are very easy to care for, and will give weeks of pleasure.

  • The plants are undemanding and can be placed in both the shade and the sun. The temperature does need to remain above at least 5-8 °C, but that won’t pose a problem in the summer.
  • Make sure that the soil never dries out, so water regularly, particularly when the plants are placed in pots or containers. The bulbs and tubers mean that the plants can survive through a slightly drier period, which is handy when you go on holiday for a week.
  • Give plant food once a fortnight to ensure lavish flowering. Remember, the plants are only for decoration and not for consumption.

Tips for keeping potted summer bulbs
Summer-flowering potted bulb plants can be kept by bringing them indoors after flowering in October or November. That gives them a hibernation period whereby the plant remains dry and the foliage dies back. The bulbs and tubers will then produce plenty of new flowers during the next growing season. You can plant them outside again from April onwards. The plants will then produce the fabulous flowers again in the summer.

More information about potted summer bulbs and other garden plants can be found at