This technique of classification groups plants into:
1. Annuals: These flower in the same year in which they are planted.
2. Biennials: These flower in the year following which they were planted, i.e, there are two years in their life cycle.: he first year is general growth and the second for flowering and fruiting.
3. Perennials: Live from year to year. These can be subdivided into the following:
a. Herbaceus perennials: In which the greater part of the plant dies after flowering leaving only a small (perennia) portion called the stock or candex close to or within the earth, to resume growth the next year, e.g., Onion.
b. Woody perennials: in which the perennial woody parts form a greater part of the plant but branches near the base and does not exceed a man’s height.
c. Under-shrubs: In which the flowering branches, form a considerable portion of the plant. The plant dies down after flowering but leaves a more or less prominent and perennial woody base.
d. Bushes: They have low branched shrubs.
e. Trees (Arboreous or arborescent plants): These have a greater height and form a woody trunk. A tree scarcely branches from the base.
f. Xerophytes: These are drought resistant plants found thriving in geographic regions of the world, with excessively high dehydration, like deserts, e.g. the cactus plant.