Fall Division of Polyanthus Primroses
by Alfred E. Brooke
This article originally appeared in the Primroses Quarterly, Volume 1, Issue No. 2, October 1943 (pages 35-36)
Dividing Primroses is not a difficult feat and does your plants a great deal of good.If not divided, they soon deteriorate.
If a maximum number of new plants is desired, divide down to single crowns, but if you wish to have a good display in the spring following division, leave two or three crowns in each new plant.
The actual division is simple. Dig the plant to be divided; remove all soil from the roots; divide into one or more plants as desired; trim the roots to about two and a half to three inches and trim off all old leaves. Don’t forget to keep divisions cool and moist before and after resetting, watering thoroughly. Occasionally you will have a plant with a tough, enlarged root resembling wood. Cut this root with a sharp knife into the desired sized new plants, eliminating as much of the old woody structure as possible.
Primroses are decidedly cool weather plants. The hot summer months are their rest or dormant season, and their long roots down in the cool, damp earth should not be disturbed until the fall growing season is about to commence. By delaying division until this season little watering is necessary and the plants do not develop a large lush growth before the winter frosts. An excessive growth during summer and fall makes Primroses particularly subject to winter damage for they have been forced and weakened through insufficient rest.
Fall division of Primroses also helps to eliminate Strawberry Root Weevil from the new plants. Weevil eggs are laid in early summer and hatch in a few weeks. The larvae immediately travel down the Primrose roots and start feeding on them. By late summer, or early fall, even the latest larvae are hatched and feeding. Division at this time removes practically all larvae from the roots and the new plants are set with clean roots ready to start natural growth and bloom freely in the spring. The writer has, for several seasons, observed that fall divisions have been free from the Root Weevils, whereas, plants which were baited, but left in place, had some larvae in their roots.
To summarize, let me repeat the advantages of fall division:
1. Primroses stand the hot weather better with a full root system.
2. Dividing should be done at the end of the dormant (summer) season so the new plants have cool weather in which to become established.
3. Late division is a great help in eliminating Strawberry Root Weevil from Primroses.
4. Don’t overlook the human element. Who among us gardeners does not, some time or other, neglect the plants not in bloom? New Primrose divisions require watering frequently during summer.