An image for people new to Meconopsis. There are 3 basic types of plants in this genus. 

1.  Monocarpic deciduous - flower after a number of years, foliage dies back totally in winter and then the plant dies after setting copious seed. 

2. Monocarpic evergreen - plant may take up to 5 years to flower - most often 3. It starts as a small rosette which over the years becomes larger until a flowering spike and seed are  produced, this then dies. These can be a lovely winter feature in the garden especially with frost on. 

3. Perennial plants that produce multirosettes and, if looked after, flower year after year. Meconopsis betonicifolia, M. grandis and the hybrid Lingholm are best known. All usually set copious seed but it should not be collected from any species until the capsules have naturally opened. 

With tall spikes of many species it may need several collections to save all the seed. If you leave it too late however, high winds can spill much of the seed.