How to combine annual flowers in window boxes

Do you dream of a balcony full of flowering annuals? Annuals in window boxes need regular care, so choose plants that not only suit the position of your balcony but also create the effect you want. They do not even have to be typical balcony plants.

Don’t be afraid to experiment

Try planting your window boxes with different kinds of annuals. You will be rewarded with a surprising display of bright colours and varying heights that is priceless. The range of plants you can use for planting is very varied, so don’t be afraid to use your imagination.

If you try combining several species, make sure that the annuals you choose for your window boxes have similar growing needs and get on well together. So don’t be afraid to try an interesting combination, for example with geraniums. You can also try planting containers and window boxes with a single species. The result will be a waterfall of flowers that many people will envy.  

How to keep annuals in window boxes flowering for a long time

You will need to look after your annuals properly. Besides basic care, some young plants need pinching out after planting. This applies, for example, to snapdragons, stocks and asters. This encourages their growth and, above all, makes the plants stronger. If you want them to flower for longer, remove the seed heads regularly so that the plant does not exhaust itself completely. Also check whether your annual has been attacked by a disease or pest. This is very common on terraces and balconies, and it can be fatal for annuals.

Classic “Czech” annuals

Geranium

Some people cannot imagine a window without geraniums. They love light and sun, and only then will they flower abundantly. They can even cope with a south-facing position. Try to protect them from rain, though. This is exactly why cottage owners praise them so much, because they can go without water for several days. Feed them about once every two weeks. Coffee grounds also make a good fertiliser for them. If you decide to overwinter your geranium, take it out of its container and wrap it in paper with a little soil. You may then have more success than me, as I have never managed it so far.

Petunia

They are the most popular balcony plant and will flower in a huge variety of colours. Give them suitable soil, a sunny spot and regular watering. The most interesting thing is that petunias are actually perennials, yet we grow them as annuals. Feed petunias with a good-quality compound fertiliser with a higher calcium and iron content.

Which annuals combine best?

Bacopa (Sutera)

It is ideal for hanging baskets, where its long shoots with small white flowers that keep on blooming will tumble over the edge and look fabulous and full. As for the compost, never let it dry out completely. Bacopa does not like dry soil. If you decide to overwinter it too, use a cool place, just as with geraniums.

Million Bells  (Calibrachoa)

They are very similar to petunias, with tiny flowers covering the plant’s long trailing stems. You will especially like them in different colours planted together and intermingling in one window box.

Thymophylla

This annual grows in a rounded mound, has finely cut leaves and a pleasant lemon scent. If you plant it at the edge of a window box, its trailing stems will spill over the edge. It tirelessly produces new bright yellow flowers that look like daisies. Don’t forget to improve the soil with a higher lime content. Also be careful not to overwater it, as this could kill it.

Fan flower (Scaevola)

It is ideal for hanging containers because of its trailing habit. In a window box, you can’t go wrong combining it with white, yellow and purple annuals. It likes full sun, sometimes partial shade. Don’t be afraid to feed and water it generously, and it will reward you.

African daisy (Osteospermum)

This annual is very striking, especially for its colours: purple or pink and white. It loves sun, but be careful not to overwater it. It really cannot stand that. The compost should not dry out completely either. Try mixing it with twinspur, torenia or garden verbena. It is just a shame you cannot pick it for a vase.

Torenia

It is a very easy plant to grow, so even a beginner gardener can manage it. Water this annual in a window box regularly, but don’t overdo it. Try to add compost at least once a month. It is most often blue, but you can also find it in pink, yellow, purple and white.

Just like any other plant, annuals in window boxes deserve your attention. Have a look at our other articles too, for example tips to help you grow annuals, or how to choose the ideal lawn mower. Or get some inspiration from a gluten-free diet.