In and Out Plant

18 May 2017

In & Out Plants: May Houseplants of the Month

The story of In & Out Plants

Merging indoors and outdoors and making the garden into a second home, or extending your interiors outwards, is a popular trend. Calla Lily, Campanula, Cockscomb, Balloon Flower and Lily fit perfectly with this: fabulous houseplants that can be placed both inside and outside and hence join the two together in a natural way. The variety of colours and shapes is overwhelming, but very different depending on the species. Campanula and Balloon Flower (Platycodon) mainly come in blue, white and pink, was lilies are widely available in orange, yellow, white and pink. The colour palette with Cockscomb (Celosia) and Calla Lilies is even more diverse, from delicate pastels through to brilliant deep shades. And you can enjoy these lavish bloomers from April to September.



These In & Out Plants originate from very different places. Calla Lily is a swamp plant which embeds itself firmly in riverbanks. The plant grows from South Africa to Malawi, often in places where the drainage of rainwater is obstructed. This creates a brief swamp-like situation during which Calla Lily stores water in its bulbs, which helps it get through the dry periods. All the Lilies that are used as houseplants are hybrids. The plant is native to Japan, China and Korea. Tropical Cockscomb originates from East Africa, South America and South-East Asia, and has now established itself in all tropical regions. The plant has been bred in the Netherlands since 1989. Prior to that, many cultivated forms came from Japan. Campanula grows in Italy, whilst Balloon Flower (Platycodon) has its roots in East Asia.


What to look for when buying In & Out Plants

  • When buying this varied group of plants, look at the pot size and whether the plants are uniform in terms of size, height, diameter and number of flowers. 
  • The ripeness varies according to species. Generally speaking, the buds must be well-developed so they can flower for the consumer. Being underripe is often the reason why flowers don’t open of buds shrivel. 
  • With the bulb crops (Lily and Calla Lily) the soil can be a bit dry, since the plants get some of their energy from the bulb. It also makes them easy to ship and at the point of sale. With Calla Lily the tubers and the plant itself can be infected with bacteria, which shows in slimy stems and the rapid decline of the plant. Yellow or drooping leaves are also signs the plant is not healthy. The tuber size (diameter of the tuber in cm) determines the number of flowers that will be produced by each plant. The same applies to Lilies. The larger the bulbs used in the pots, the more buds there will be per stem. With the Lily it’s important to check that the bulbs are properly rooted and are not loose in the pot.
  • With Campanula, Balloon Flower and Cockscomb it’s very important that the soil is slightly damp in order to prevent the plant from drooping. Water regularly, including at the point of sale. Do make sure that the water only goes on the soil and not the foliage and flowers, since botrytis can otherwise rapidly infect the plants in the form of grey mould. It is particularly important to check the plant carefully for this fungal disease in the case of plants that are supplied in cellophane or in wrapped trays. 
  • Give these plants enough light at the point of sale - if conditions are too dark, they will start to stretch. These species can also suffer yellowing and drooping leaves. 

Choice of range

The range of plants that can be used both indoors and outdoors is growing rapidly. There are many different varieties of each species, many which are increasingly being sold by cultivar name. 

Calla Lily (Zantedeschia) comes in both large-flowered and small-flowered varieties in almost all the colours of the rainbow: white, yellow, pink, purple, lilac, salmon, orange. The leaf colour can also range from green to speckled. 

Pot Lilies also come in various cultivar groups. Hence there is the Asiatic Group (small buds, delicate leaf, bright colours), the Oriental Group (coarse buds and leaves, large flowers with a strong scent, particularly white and pink varieties), the Longiflorum Group (long white flowers) and the LA Group (hybrid of Longiflorum x Asiatic Group, particularly with pastel colours). 

Cockscomb has been intensively bred in recent years to produce attractive new varieties with fantastic new flower shapes and colours (bright, pastel and bicoloured). There are three shapes: the C. Cristata Group (cockscomb), the C. Plumosa Group (plume cockscomb) and the C. Spicata Group (tail-shaped small flowers). The latter group in particular provides most of the varieties that are used as In & Out Plants. 

The Balloon Flower range is restricted to 3 colours: white, blue and pink. Before the flowers open, they are shaped like balloons. The flowers themselves consist of 5 petals, and the foliage is somewhat grey in colour.

Campanula has an extensive range which characterised by white, blue and bi-coloured varieties. The variety C. isophylla, with its star-shaped flowers, is best for use as an In & Out Plant. The range is more extensive for the garden, but is less suitable for use both indoors and outdoors. 


Care tips for consumers

  • All In & Out Plants prefer a cool and light spot indoors to ensure the longest possible flowering. In the garden they can tolerate both full sun and partial shade. 
  • As bulb crops, the Calla Lily and the Lily are the easiest to care for: watering once a week is enough. 
  • Campanula, Cockscomb and Balloon Flower have softer leaves, and therefore evaporate more moisture, meaning they need more water: the soil should always be slightly damp.
  • For profuse flowering give the plants and food every two weeks and remove wilted flowers for extra-long flowering.

Sales and display tips for In & Out plants

In & Out plants are suitable for containers, pots and hanging baskets. Combine the various species together by colour, or create colourful mini gardens in the display that makes clear that the plants can be used both in the living room and on the patio or balcony. The plants combine well with summery accessories such as butterflies, decorative insects and other botanical elements. 

In and out Houseplants

Credit: Flower Council of Holland








In and Out Plant