14 MASS. EXPERIMENT STATION BULLETIN 330 



Culture of Bulbous Iris 



Briefly stated, the culture in the open of bulbous iris is the same as of the 

 common hardy tulips (Darwins, breeders, and cottage varieties). The bulbs 

 are received from the dealers early in the fall, about October 1. They should be 

 planted immediately in well-drained soil and in a sunny location. Bulbs should 

 be set 4 — 5 inches deep and 4 inches to 1 foot apart. They will usually be set 

 in rows, but planting in compact beds is perfectly satisfactory. The bulbs 

 will soon begin to grow and most varieties will send up green spearlike shoots 

 to a height of 4 or 5 inches before freezing. This development is apt to cause 

 anxiety to the novice, as it appears to be a sure promise of winterkilling. How- 

 ever, this is the habit of the plants and no harm seems to follow. 



It has been the usual, though not invariable, practice to give some winter 

 protection. Sometimes a straw mulch has been used; but the commoner 

 method, and the one recommended is to wait till the ground is frozen and then 

 to place a few evergreen boughs over the beds. These evergreens will hold 

 the snow and the snow will provide all necessary insulation. 



In the books, a dressing of lime has often been recommended for iris bulbs. 

 Though the soil here is normally acid, and though liming has been tried in 

 several instances, no results have been demonstrable. 



By July 1, the flowers will be past. Once more the bulbs may be treated like 

 tulips. During the month of July they may be lifted, dried off, the young 

 bulbels separated, and the whole replanted in late September. Or if it is 

 more convenient the bulbs may be left entirely alone where they stand. Some 

 varieties will maintain their place in the garden for several years without any 

 further bother: but most varieties tend to run out under this laissez-faire 

 system. 



Since the bulbous irises are especially superb for cutting, and since cutting 

 must always take heavy toll of the foliage, it can hardly be expected that good 

 flowers will be produced by the same bulbs year after year. It will be necessary 

 on this account to keep bringing in young and vigorous bulbs from the natural 

 increase or else to buy fresh bulbs annually. This latter practice is more 

 expensive, but it gives better results. 



The present bulletin is concerned primarily with the garden culture of bul- 

 bous iris, but the fact should at least be mentioned that a principal portion 

 of the bulb crop is used by florists for forcing in their greenhouses. The cut 

 flowers of the most sumptuous beauty are offered in the florists' stores during 

 the midwinter months. The Department of Floriculture at Massachusetts 

 State College has regularly forced small quantities of iris each winter for many 

 years past and testifies to their great desirability in this role. 



Making a Beginning 



On the basis of the experience here set forth it would seem proper to recom- 

 mend the bulbous irises (meaning varieties of the so-called Dutch, Spanish, 

 English, and Tingitana groups) for general cultivation by amateur gardeners 

 in Massachusetts. They seem likely to give abundant satisfaction in home 

 gardens wherever the common hardy flowers are grown. In cultural require- 

 ments they are most closely allied to tulips and crocus; anyone who succeeds 

 with these common bulbs will hardly fail with bulbous iris. 



