Through his years at Hadlow College, hellebores have remained a constant passion for Alex Rennie. He was a student there during the 1980's, and returned as Head Gardener in 1996, where he was responsible for his favourite plants: hellebores.
The National Collection was set up 20 years ago by Kemal Mehdi, the curator, and Alex recalls becoming involved with the hybridising process whilst he was a student.
 
  
 
Hellebore production has become highly commercialised since Alex graduated from Hadlow. The pretty hybrids that tempt us in garden centres  - with their elegant single, anemone-centred, double, plain, spotted or blotched - are probably just one of several popular strains of Helleborus x hybridus.
Hadlow College has its own strain, as do other nurseries such as Blackthorn Nursery in Hampshire, and Ashwood Nurseries in Birmingham was one of the first to produce on a large sale. 'There are so many named strains these days, it's hard to keep up, but many of the seedlings are just as good.' says Alex.
 
Breeding process 
When Alex is crossing hellebores to create new hybrids, he first removes the flower from the male parent and floats it in water in the glasshouse.  This releases the pollen. Alex then removes the anther with tweezers and takes it to the female plant, whether its under glass or in the garden. it must be a closed flower bud so he knows it hasn't been pollenated. He places the anthers on the stigma, repeating the procedure three days in a row. This usually happens in February or March. 'It's important when making a cross that you make a note of the parents,' he says.
 
In May, the flowers are placed in Muslin bags to collect the seeds. Alex sows the seeds as soon as possible, using clay containers in a cold frame. The seeds may germinate at any time, but some re stimulated if there is a heavy frost followed by a mild spell. The plants are potted from on during November using a compost made from a mix of loam and composted bark. This mix has helped the college to reduce its use of peat.
 
The parent plants are only chosen once they've been shown to produce valuable offspring. The majority of hybrids are similar to their parents, with the same colouring, marking and flower shape. However, because it takes seedlings three years to flower, there's a long wait until you know what you've created.
 
H x hybridus plants are also known as Lenten roses, and most are produced by seed. All can be divided, the parents are sometimes split, but because it can take the plants three years to recover, it's easiest if you save some of the naturally produced seedlings. These should be allowed to mature, while those that are similar to or better than the parent should be retained. Division should be avoided because it can leave the plants open to infection.
Of the species, H. argutifolius and H. foetidus are always grown from seed. These cannot be divided as they are different in structure, with shoots produced from one point at the base, and consequently aren't possible to divide.
 
If you fancy breeding new plants you can either use Alex's system of removing the male flower parts or simply rub together the flowers you've chosen and collect the seeds. However, hybrids will self pollinate and many of them will produce lovely offspring so it's really only necessary to make selected crosses if you're trying to transfer one particular characteristic into a new plant.
 
Growing the best 
Hellebores thrive in moist, fertile soil and dappled shade, so dig the ground thoroughly before planting. Add organic matter, such as leafmould, spent mushroom compost or well-rotted manure.  Although they are quite resilient and will grow almost anywhere, they do best in well-drained conditions. The dappled shade beneath trees is ideal, but ensure the soil doesn't dry out during the summer. Protect plants from cold winds and mulch in July to encourage new buds. Mulch them again around Christmas, and remove the old leaves. 
 
Alex recommends both H. argutifolius and H sternii, because these will grow happily in a sunnier position than other hellebores. The large, structural leaves of the H. sternii are a metallic blue-green, which makes an excellent backdrop among spring flowers. The best planting partner for hellebores, especially the hybrids, is snowdrop.
 
There's a myth in gardening that hellebores shouldn't be disturbed once planted, but it's only with H. argutifolius and H. foetidus that special care should be taken because of their small, fine root systems and heavy top growth. They are both included in the National Collection and are worth growing in your garden.
 
Alex's National Collection of Hellebores is at Broadview Gardens, which is set within the grounds of Hadlow College, Hadlow, Tonbridge, Kent, TN11 0AL.
 
 
Readers day
We have organised a guided tour of the Hellebore Collection with Alex Rennie exclusively for Gardens Monthly readers. The tour plus tea with the Gardens Monthly team will take place on Wednesday 24 February 2010 at 2:00pm and costs £3. Limited spaces are available so booking is essential. Ring 0844 412 2262 or email gardens@myhobbystore.com