You can explain that the purpose of a blooming plant is to produce seeds. That is its life function. Once this object is accomplished many plants either stop blooming or taper off. But, if blossoms are snipped off as they fade, the plant will keep on trying to make seed by producing more blossoms.
This principle also applies to some vegetables. Spring-planted broccoli, for instance, will bear all through the fall if all florets are cut as soon as they are edible. Most varieties of
snap beans will produce over a much longer season if mature beans are kept picked as fast as they appear. Blossoms of chives should be removed, too, for continuing production of tender blades. Cucumbers, zucchini and summer squashes should always be picked before they ripen their fruits and develop large seeds.
The idea that there is something pretentious and highbrow about the technical language of plant names is an unfortunate delusion.
Explain to any child under your supervision, right in the beginning, that knowing plants only by their common names is like knowing people only by their nicknames. Point out that it is all very well to call a friend Shorty. But if he wants to write a letter to Shorty, or identify him to strangers, he must also know his surname and his christened name. Only his full name, John Rogers Smith, will distinguish him from other Shortys.
Illustrate your point this way. Common names do not always mean the same plant to all people. Bluebells, for example, in one locality may mean the English bluebell (Scilla non-scripta). In another this name may refer to the grape hyacinth (Muscari botryoides). In still others it could mean Mertensia virginica, Campanula rotundifolia, or Polemonium. These are all different flowers, but somewhere, someone calls each of them bluebells.
At first all the child need learn is the generic name. Species and variety can come later. Knowing that grape hyacinths are Muscari or that pinks are Dianthus equips him to look them up in catalogs or reference books.
Remind him also that many plants are so commonly called by their botanical names that he may have learned automatically to say names like alyssum, coreopsis, lobelia, delphinium
and anemone, and is using Latin names without realizing it.
Children will also quickly grasp the idea that certain varietal names are always the same and easy to decode. For instance, azurea always means sky-blue, gracilis slender, grandis large and compacta compact. As a garden writer once said, learning to speak the scientific language of gardening is much like swimming-not so hard once you get wet. Certainly it is an indispensable part of the gardening craft.