Alpine Garden Society

Ulster Group

Plant of the Month, February  2008
Spring crocuses - by Mark Smyth
A useful addition to any garden or alpine house are the spring flowering Crocus. They perform much better in the alpine house where the rain and wind does not ruin them. Some can be bought very cheaply from specialist suppliers such as Janis Ruksans in Latvia, Leonid Bondarenko in Lithuania or closer to home from Miniature Bulbs.


Crocus corms, as with all Ďbulbsí, are best planted within days of their arrival. All my collection are now in 4Ē square rigid plastic pots but you can get away with smaller ones. The larger pot will not dry out so quickly in the glass house.  

My mix for these again follows the Ian Young mix of 2 parts grit, 2 parts horticultural sand and one part leaf mould. This is mixed in a wheel barrow with one cup of bone meal. 

Crocus cviijcii

Donít worry if a mould quickly grows if the mix is left for a few days. This is just microbes and fungi breaking down the bone meal. Itís amazing how fast they grow. I just mix everything again when I come to use it. The Crocus are planted 2/3rds down and grouped together but without touching.
On September 1st give the pot/s a good soak from a controlled water source. On October 1st repeat this and donít water again until the flowers and leaves are up. I only water when the surface dries out. 
If you want to grow from seeds make sure you have a tiny paint brush handy for when the flowers are open. You can either have one for each species or try pot luck and cross pollinate them all. The former is better. Watch out for aphids on the emerging leaves. They are a major pest and will spread virus through a collection. 

Crocus imperati

Crocus chrysanthus

 When the flowers are over, the pots can be set outside to be watered naturally. It is now that liquid feeding can begin. Only do this when the weather is mild. I use a dilute mix of one heaped teaspoon of Sulphate of Potash in a 9L watering can. This is water soluble so there is no worry of over feeding. SoP helps build the corms for the following season. 
As the leaves start to turn yellow the ovary that has spent the spring below soil level elongates until it is at the surface. As it matures and drys out the seeds can be collected and sown in their own pots.When the leaves have yellowed let the pots dry out and remove the old leaves. Some corms donít like to be baked in summer sun so these can be stored under the bench. Repotting is done every other year.  

Crocus baytopiorum

Flowering time can start at the tail end of the autumn flowering Crocus season around late November and depending on weather can extend in to late February. Those grown under glass are almost always a month ahead of those in the garden  
If you want to build a serious collection I would stay away from garden centre Crocus. From experience they are badly mixed up but more than suitable for a garden display  

The best web sites for Crocus images are

Crocus Pages

Marks Garden Plants soon to be updated

The pictures show some of my favourites

                                              Crocus 'sunspot'