-m- 



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from as little as two to as many as twenty species. 

 They have included annual, perennial, and biennial, 

 as well as grass species. Two or three annual species 

 in a mix has given us good results. Annuals afford first 

 season color as well as act as a nurse crop protecting 

 young perennial plants during that time. California 

 Poppy, Bachelor Button (Cornflower), Baby's Breath 

 and Cosmos are four annual species that have per- 

 formed particularly well throughout the state. Of the 

 many perennial species used to date, some tend to 

 be more site specific than others. For example, we 

 have found that Wild Lupine does extremely well 

 north of Plymouth, but only marginally so to the 

 south. Warmer temperatures and aphids seem to be 

 the principal factor in their lack of success. Addition- 

 ally, in well-drained high-moisture locations such as 

 highway shoulders or slope areas with high surface 

 water movement. Lupine has exhibited intense growth. 

 Dame's Rocket, Ox-eye Daisy, Lanceleaf and Plains 

 Coreopsis, Black-eyed Susan, Purple Coneflower and 

 Farewell-to-Spring have also done consistently well 

 throughout all zones and growing conditions. In select- 

 ing any seed, we have always made it a point to buy 

 from a reputable source that specializes in wildflower 

 seed and can supply detailed information on indi- 

 vidual species as well as specially formulated mix- 

 tures. 



SITE PREPARATION: HERBICIDE APPLICATION 

 Approximately 50% of the wildflower sites we have es- 

 tablished were subject to herbicide application. In ev- 

 ery instance, herbicide has effectively reduced the 

 competition that grass and other established species 

 have on wildflower growth. Locations where herbicide 

 had been applied as part of site preparation exhib- 

 ited a denser and more uniform stand of wildflower 

 growth than those that were not. 



SITE PREPARATION: ROTOTILLING, 

 DESODDING, DETHATCHING 



We have concentrated much of our effort on determin- 

 ing the effects of site preparation on wildflower suc- 

 cess. A variety and combination of site preparation 

 techniques have been used during the past several 

 years. They have ranged from simply dethatching and 

 raking out a site in preparation for seeding to me- 

 chanical desodding and rototilling of the exposed 

 bare earth. The intent of site preparation is to afford 

 the best opportunity for desirable seeds to germinate 

 and establish themselves with a minimum of weed 

 competition. 



Shallow rototilling of all sites is recommended. This 

 serves to create a loose, friable seed bed. However, 

 tilling should be kept to a depth of only about 2 

 inches. Deeper tilling may promote weed growth by 

 bringing that seed to the surface. 



in order to gauge the significance of desodding a 

 wildflower site, a number of small adjacent test plots 

 were established. All were treated with herbicide; half 

 were then desodded and rototilled while the treated 

 sod on the remainder was simply rototilled into the 

 existing soil. All were then identically prepared, 

 planted, and maintained. Wildflower germination and 

 growth were slightly better on the desodded sites. 



However, we feel that this is attributed to greater 

 seed-to-soil contact on these plots. If the tilled sod 

 were afforded better seed-to-soil contact through roll- 

 ing or tracking, we feel equal production would result. 

 As a possible alternative to sod removal and roto- 

 tilling, several sites were treated with herbicide and 

 then mechanically dethatched. The intent was to de- 

 termine a procedure that would apply to steeper 

 slopes where erosion as a result of tilling may be a 

 problem. With a seed mix consisting of approximately 

 9 species, first-year results indicated a general failure 

 with only sparse production. Second and third-year re- 

 sults showed an eventual fair-to-good establishment of 

 only one species, Lance-Leaved Coreopsis, in addition 

 to reestablishment of the original grasses. As a result, 

 this method of site preparation was determined to be 

 unacceptable. 



SITE AMENDMENTS: COMPOST/SLUDG'E, 

 LIMESTONE, FERTILIZER 



In many instances, we have supplemented existing 

 soils with commercially manufactured compost mate- 

 rial. While it is possible to plant wildflowers in poor 

 soil, the addition of approximately 2" of compost, 

 lightly tilled into the existing soil not only serves to 

 increase nutrients and moisture retention, but is a 

 growing medium relatively free of competing weed 

 seed. The ingredients and quantity of commercially 

 produced composts vary greatly. Selecting a compost 

 that assures a weed seed-free formulation either by 

 determining its individual components or composting 

 process is essential. 



Generally, fertilizer is not recommended in wild- 

 flower establishment unless the existing soil nutrient 

 quality is poor. Fertilizer may encourage the growth of 

 unwanted weeds. In instances where we have estab- 

 lished wildflower in poor soil and have not amended 

 it with compost, fertilization has been beneficial in 

 plant production. Generally, a soil pH range of 6.0 to 

 7.0 is considered ideal for wildflower establishment. 

 The addition of limestone to meet this range is rec- 

 ommended. 



SEED APPLICATION: HAND BROADCASTING, 

 HYDROSEEDING AND OTHER MECHANICAL 

 METHODS. 



Approximately 50% of our wildflower fields established 

 to date have been hand-seeded, using sand as a 

 bulking agent and spread indicator. Because of the va- 

 riety of seed sizes, hand-broadcasting provides the 

 greatest uniformity in seed coverage. Hydroseeding, 

 although less precise, has been done on the remain- 

 der of our fields These are the only two methods of 

 application the Department has employed to date. 

 Other states have successfully used other methods of 

 seed delivery which are currently under consideration. 



POST APPLICATION: ROTOTILLING/TRACKING, 

 MULCHING, AND WATERING 



Seed-to-soil contact is essential in assuring maximum 

 germination of wildflower seed and initial vigor of new 

 seedlings. Rolling of newly applied seed has realized 

 the greatest degree of success and should be a key 

 step in the wildflower establishment process whenever 



February &v March 1994 



17 



