FORCING 



FORCING 



601 



good knowledge of the plants; (2) proper preparation; 

 (3) a period of rest; and (4) proper care after the plants 

 are brought into heat. 



Those plants force most easily which bloom in spring 

 and early summer. Late-blooming kinds, like Rhodo- 

 dendron maximum, Clethra and Hydrangea paniculata, 

 var. grandiflora, do not give good results. No success is 

 obtained with asters and goldenrod, unless they are 

 retarded. These points must be studied out by the 

 grower. 



Trees and shrubs should be specially prepared for 

 Forcing by careful cultivation for 1 or 2 years before 

 use. They can be planted out of doors, with plenty of 

 room to develop, or they can be grown in pots; the lat- 

 ter method being used with vigorous plants, which are 

 apt to run to growth, without developing flower buds 

 Close pruning is necessary, and root-pruning is helpful 

 Grafting, which has a tendency to dwarf and hasten 

 maturity, is also used with strong growers. Sometimes 

 both growing in pots and grafting are employed, as in 

 lilacs. Query: Could we learn anything in these par- 

 ticulars from the Japanese method of dwarfing plants? 

 A plant fit for Forcing must be compact, both top and 

 roots; economy in space is essential. It is now possible 

 to obtain from the French, Dutch and Belgian nurseries 

 many plants grown for this purpose. A few come pot- 

 grown, but most of them are from the open ground : very 

 little of this work is done in American nurseries. Figs. 

 849-851 show the methods of preparing 

 woody plants for Forcing. 



Herbaceous plants should be pre- 

 pared for Forcing with equal care, and 

 the process may require several years. 

 The removal of the flower buds and 

 growth, under high cultiva- 

 tion, in close, compact 

 clumps, apparently produces 

 the same results that prun- 

 ing and grafting accomplish 

 for trees and shrubs. Fig. 

 852 shows the root-clump of 

 an herb prepared for Forc- 

 ing. 



Plants that have once been 

 forced are commonly thrown 

 away. It is generally cheaper 

 to buy new stock, but lilacs, 

 azaleas, etc., can be planted 

 out and will recover suffi- 

 cient strength in 2 years for 

 a second Forcing, or for 

 other use. Some species, 



like Viburnum plica turn, staphylea, colchicum, etc, if 

 grown on in pots after Forcing, may be again forced, and 

 seem to do better the second year. This is probably ex- 

 plained by the fact that insufficient preparation was 

 given for the first trial, the first Forcing being really 

 "proper preparation" for the second Forcing. 



Hardy plants must have a period of rest for success- 

 ful Forcing, the time required varying in different 

 species. One cannot tell, except by experiment, that 

 Paper White narcissus will force easily in November and 

 December, while the double Von Sion will not; the in- 

 dividual equation of each kind is an element which must 

 be considered. There is a popular notion that freezing 

 will shorten the time for resting, or, at any rate, is con- 

 ducive to the welfare of the plant. This idea does not 

 seem to stand any practical test. After potting, do not 

 subject the plants to severe frosts (10 or 12 P.), or else 

 the roots, now much exposed, may suffer. The large 

 buds of lilac and rhododendron may also be injured if 

 frozen hard. 



Pot the plants as soon as they ripen their growth in 

 autumn, beginning in September with herbaceous stock, 

 and continuing until severe frost. It is possible, but 

 not desirable, to lift some things after the ground is 

 frozen hard. Plants received from abroad are potted on 

 arrival, or, if furnished with a ball like azaleas (Fig. 849) , 

 they can be stored and not potted until brought into heat. 

 Dutch bulbs are boxed or potted as they are received, 

 and buried in the earth or piled in stacks and covered 

 rith enough leaves and litter to exclude frosts. Lily-of- 

 the-valley, astilbe and dicentra are kept in their pack- 



852. Dicentra roots prepared 

 for forcing. 



ing cases in a cool pit until ready for use. Large plants 

 in tubs and boxes can be covered with leaves and kept 

 out of doors, but most plants should be stored in a cool 

 cellar, pit or frame kept at a temperature of 35 F. ; a 

 temporary variation of 5 either way does no harm. It 

 is well to delay this storage until as late in the season as 

 possible, but it must be done before severe weather. 



853. Forcing Lily-of- Valley in pots. 



They can be stowed compactly, in several tiers if neces- 

 sary. It must be remembered that no growth is to be 

 allowed while stored; it is their period of rest, and this 

 must be enforced: Good ventilation must be given on 

 bright days and every precaution taken against an ac- 

 cumulation of moisture: if the plants are well watered 

 when put away very little will be required afterwards. 

 Dampness is most serious with evergreens, like kalmia, 

 and such things as Phlox subulata. This stock should 

 have the airiest positions, or it can be placed in shallow 

 frames 2 ft. deep, which are drier than deep pits. In 

 severe weather the pits are often covered with snow a 

 week or more, but the plants will not suffer if this hap- 

 pens but once or twice during the winter. At such times 

 mice and squirrels will make trouble unless trapped or 

 poisoned. 



Nothing except retarded plants, a few bulbs and one 

 or two kinds of prunus should be brought in before No- 

 vember. December 15 to January 1 is as early as it is 

 safe to begin Forcing most hardy plants ; it will be found 

 that as the days lengthen the results will be more satis- 

 factory. At first the plants must be kept cool, 45 F. or 

 thereabout. Syringe twice a day until the buds swell: 

 after growth starts the treatment is the same as that 



854. Forced Trillium. 



given greenhouse plants, and they can be put in a much 

 warmer house if so desired. It is at this time that care 

 in handling, particularly in the matter of heat, makes it 

 possible to time the period of blooming so accurately^ 

 but it is impossible to give any general rules to satis- 

 factorily cover these matters. 

 A few plants, like lily-of-the-valley, can be placed di- 



