Wander round Knights Garden Centres now and you will see racks of colourful summer-flowering bulbs in packs. All are suitable to plant now and will bring colour to your garden from July to September. But which are best for pots? Which are hardy and which flower longest? To help you decide what you buy, when you visit this week, here is my simple guide to the most popular.
Begonias
There are lots of different begonias but the most spectacular are the tuberous begonias. The large or medium-sized blooms come in a huge range of colours. Some are upright in habit while other have an arching habit (pendula), ideal for baskets .
Are they hardy?
No – they need to be started in a pot in a warm place such as the windowsill. Plant the tuber just below the surface in a pot, water sparingly and keep warm to sprout them and plant them out in May when there is no chance of frost.
Can you plant them direct in the garden
Not really
How long do they bloom?
Once they start to bloom they keep on flowering right till the first frost of autumn. You can keep the tubers for next year.
Are they good for pots?
Absolutely. They are perfect for pots in sun or part shade and they also look good in window boxes and hanging baskets.
Lilies
Are they hardy?
Yes. Unlike most summer bulbs, lilies are hardy. They can be planted in winter and from now till April. But the bulbs are prone to drying out so get them in the ground as soon as possible.
Can you plant them direct in the garden
Yes. Plant them about 10-15cm deep in a spot in sun or part shade. Lilies like a soil rich in organic matter so mix in some compost.
How long do they bloom?
It can vary but each bulb produces one stem with flowers at the top. These can last from two weeks to a month.
Are they good for pots?
Yes. Lilies are great in pots but the pots need to be quite deep because you need to plant the bulbs deeply. It is always best to plant three to seven together because they are tall and slender. Heights vary a lot so check the pack. Very tall lilies can be top-heavy in pots. Most lilies grow well in multipurpose compost but Oriental lilies (such as Stargazer) need ericaceous compost.
Dahlias
Are they hardy?
No. Although you may be lucky and find that old plants sprout in spring, in general dahlias will be killed if the shoots or the tubers are frosted.
Can you plant them direct in the garden
You can, and the tubers will be protected from frost if they are under the soil. But the new shoots can be killed by spring frosts. So if you are planting direct in the garden, delay that till late March or April. It is far better to start your dahlia tubers in pots indoors in a warm but bright spot. They will then be well-established and ready to bloom when you plant them out in May. Remember that slugs and snails also like dahlias.
How long do they bloom?
Dahlias are great value because they may start as early as June and then continue till October. Watering, feeding and deadheading will help the plants to keep blooming.
Are they good for pots?
Dahlias are hungry and thirsty plants and do best in the open garden. But if you look after them with water and fertilise them the smaller kinds will thrive. Taller kinds are unstable in pots so choose the dwarf kinds.
Eucomis (pineapple lily)
Are they hardy?
This is questionable! Look in old books and it will say no. But many, if they are planted deeply so the bulbs is well below the level that frost can penetrate, will prove hardy. They then come into growth in May so avoid frost damage to the foliage. I always grow them in pots the fist year and keep the pots dry and free of frost the first winter and then plant them out.
Can you plant them direct in the garden
Yes, if they are planted deeply. They need a sunny spot and well-drained soil. Heavy clay and soil that is wet in winter is not suitable.
How long do they bloom?
They tend to bloom in August or September and the flower stems look good for several months
Are they good for pots?
Yes. If you have clay soil I would be wary of planting them outside and would treat them as patio plants in pots.
Gladioli (gladiolus)
Are they hardy?
In well-drained soil gladioli will survive the winter in the soil but the corms divide and produce a lot of foliage if left undisturbed so it is usually best to lift and store them over winter.
Can you plant them direct in the garden
Yes. It is best to plant them where they are to flower, in a sunny spot. You can plant them from March to May. If you have a pack of ten, if you plant half in late March and half in late April you will get a staggered flowering time.
How long do they bloom?
Each corm will produce one stem. Each stem will produce ten to twenty flowers, depending on the variety and the size of the corm. Each stem lasts for about two weeks.
Are they good for pots?
Because of their height and relatively short flowering period gladioli are not the best for pots although they will grow perfectly well in pots.
Trigridia
Are they hardy?
Not really, although they may survive winter in well-drained soil in a warm spot. It is best to lift the corms in autumn and store them in a dry, frost-free place.
Can you plant them direct in the garden
Yes, you can plant them in late March or April in a sunny spot where they are to bloom.
How long do they bloom?
Each, amazing, flower lasts just a day but each stem produces about ten blooms, in succession for many weeks. They are usually in bloom in August. Plant in a clump of at least ten bulbs to be sure of a few flowers open each day. They are not expensive and the flowers are so amazing they will enchant you each day.
Are they good for pots?
The plants are a bit scruffy and they need support. They will grow perfectly well in pots.
Growing your own Fruit and Veg
I am delighted to be back at ‘Knights’ March 5th and 6th to present a talk on growing your own fruit and veg.
The event includes tea and cakes and then the talk. You can find all the details here