These 5 flowers are unusual but really easy to grow – and will guarantee extraordinary displays in your garden

If you're looking for something that looks a little different in the garden this year, there are plenty of easy but unusual flowers you can grow right now.

The list of fruits, flowers and vegetables you can plant in May is long, and that means there's a huge selection of blooms to choose from. Sure, learning how to grow roses and other popular flowers is always going to be rewarding, but what about the more unique kinds?

I checked in with the experts to find out which unusual but easy flowers you should add to your list.

1. Fritillaries

Fritillaries are a great example of easy but unusual flowers you can grow in your garden. These bulbous perennials are available in a huge range of colours and patterns, and they're fascinating to look at.

'If you're after something a little out of the ordinary, the fritillaria family is a brilliant place to start,' agrees Rachel Cole, seed manager at Mr Fothergill's.

For something really outside of the box, you'll want to keep an eye out for the more interesting varieties.

'Fritillaria meleagris, often called the ‘snake’s head’ fritillary, boasts exquisite, snake-like patterns on its nodding flower heads,' explains Rachel. 'For more dramatic flair, try Fritillaria imperialis, also known as the Crown Imperial. These produce luxurious spikes topped with clusters of bell-shaped blooms in vivid orange, yellow, or red, perfect for adding structure and elegance to borders or large pots.'

Usually, you'd plant fritillaria bulbs in the autumn, but you can buy ready-grown potted plants now.

Where to buy fritillarias:

• Thompson & Morgan: Buy Fritillaria meleagris as potted plants.
• Sarah Raven: Pre-order Fritillaria imperialis 'Orange Beauty' bulbs now for September.

2. Passion flower

Also known as Passiflora, passion flowers are among the most striking and unusual-looking flowers out there. They're really easy to grow, and popular garden trellis ideas - that's where mine grow, and they flower effortlessly during the summer.

'This is a showstopping, easy-to-grow climbing plant with unusual, beautiful flowers that bloom profusely from summer to autumn,' says Julian Palphramand, head of plants at British Garden Centres.

'Passiflora basks in full sun and grows best along a trellis, fence or up a pergola. Water it regularly, but don’t let the soil get too wet, as it hates being waterlogged.'

Passion flowers are also great climbing plants for pots, so if you're out of ground space, you can grow them in a container instead. Just make sure you position it next to something they can climb!

Where to buy passion flower:

• Crocus: Order a Passiflora caerulea plant.
• Thompson & Morgan: Passiflora 'Purple Haze' has bright purple filaments.

3. Alliums

Alliums aren't the least common contenders on this list, but their architectural blooms are striking to look at. Like fritillarias, the best time to plant allium bulbs is in the autumn, but you can buy potted plants and add them to your garden now.

'Alliums bloom abundantly from late spring into early summer and come in a surprising spectrum of shades, not just the classic purple,' says Rachel from Mr Fothergill's. 'Think white, deep pink, and even rich burgundy and near-black hues.'

Thanks to their height, alliums make brilliant garden border plants. Just make sure the soil is well-draining and receives plenty of sun.

Where to buy allium plants:

• Gardening Express: Rachel recommends Allium cristophii for its glittering, star-shaped heads.
• J. Parker's: Allium 'Red Mohican' is another eye-catching choice, which Rachel describes as 'a tall, show-stopping deep red variety with cheeky tufts on top'.

4. Zinnias

Zinnias are like the rainbow personified: bright, cheerful, and a spectrum of colour. They're another recommendation of Rachel's if you're looking for easy and unusual flowers to grow.

'These sun-loving flowers bring big rewards from minimal effort,' Rachel says. 'Sown directly from April to May, they’ll continue blooming right up to the first frosts.'

It's the perfect time to plant zinnia seeds, so stock your seed tin!

Where to buy zinnia seeds:

• Mr Fothergill's: Rachel recommends Zinnia 'Envy' with striking lime green blooms for a modern twist, or Zinnia 'Sombrero' for bold red and yellow flowers.

5. Canna lilies

If you're looking for unique, showy blooms, canna lilies are a timeless choice. For all their glamour, they're relatively easy to grow, too.

'Canna have exotic-looking flowers, and they are simple to grow,' agrees Dickon Harding, gardens and landscape manager at Raby Castle, Park and Gardens.

Like zinnias, canna lilies love the sunshine, and a sheltered spot with well-draining soil is ideal.

Where to buy canna lilies:

• Sarah Raven: Pre-order the beautiful Canna 'Cannova Bronze Peach' F1 now.
• Suttons: Canna x generalis Cannova 'Gold Leopard' boasts a leopard print pattern.

Our list of easy but unusual flowers to grow is by no means exhaustive, but hopefully it'll give you a little inspiration this year. Which varieties will you be trying?