They are flower bulbs for spring planting and summer flowering. Most of these bulbs fears frost and it is therefore necessary to plant them in spring. Some species also continue the flowering after the summer until the first frosts. In flower beds, in rock gardens, in flower boxes, they can replace those bulbs that have finished the spring flowering.
Lots of spring bulbs produce flowers with long stem, ideal for cutting: Gladiolus, Lilium, dahlias, etc..
The depth of planting measures, in cm, the height of the earth that covers the bulb.
The roman numbers for the time of planting and flowering indicate the months of the year from January (I) to December (XII) in the northern hemisphere.