Alliums are members of the onion family. They are stylish plants, most varieties with tall stems and large blooms with the added bonus of being easy to grow. If I could only choose one it would be Purple Sensation. It is easy to cultivate, demanding only a sunny spot in a reasonable well drained soil. It flowers in late May and early June, it seeds itself generously without being a pest At around 3ft it towers airily above border perennials that are still to flower and when they eventually finish flowering the seed heads are still a joy to see. Flower arrangers value them for spraying gold and silver for Christmas arrangements.
Globemaster is a variety that will give the garden a wow factor, it is a lighter shade of mauve than Purple Sensation but has spherical clusters of flowers nearly the size of a small football, again used lots in flower arranging. Plant in clusters of three or five along the whole length of the border. A magnificent sight in May to June .
There are lots of smaller front of the border alliums. My third choice would be one that grows between 12 and 18 inches high and has starry flowers that look as if they have been cut out of pink metallic foil. This is Allium christophii. It is a real stunner with orbs of flower up to 9 inches across that shimmer and sparkle in the late spring sunshine.
Bulbs should be planted in early autumn, not long now! Plant at a depth of 4 times the diameter of the bulb. Find a spot that drains well and will get full sun. After planting, water well to settle soil around the bulbs.
Allium bulbs should be divided every 3 to 4 years. Do this after plant has died down. Simply dig around the plant with a trowel and lift bulbs out. Separate gently, replant some in original position, plant others straight away in new spot or pot up and give to friends.
There is far more to find out about alliums so good reading. Buy some bulbs, plant out and enjoy!