190 
Overcoming Dormancy 
in Tree and Shrub Seed 
Many seeds, especially of trees and shrubs, 
fail to germinate even when one would con- 
sider every condition favorable. This con- 
dition is known as being dormant and is 
caused by either a hard seed coat prevent- 
ing moisture and oxygen from reaching 
the embryo or some condition of the embryo 
itself which prevents its germination until 
more favorable conditions appear. 
Either one may be the cause or again 
both may be the cause. In nature such 
seeds may remain for 2 or more years be- 
fore germinating for what is two years in 
nature’s work shop? But with man, this 
is a vexing problem, especially in the nur- 
sery or garden, never the less, it is an 
important factor in the survival of a 
species. 
There are several methods that can be 
employed to over come dormancy but 
while one or more of these may prove 
successful, there are cases where it is im- 
possible to over come the dormancy and only 
time will accomplish it. 
There is not a great deal of recorded in- 
formation on the subject and one really 
should know what is and what is not the 
proper treatment for each species but to give 
a general idea of the treatments, it can be 
stated that one should first consider the 
seed coat. 
If there is an impermeable seed coat, by 
soaking in warm water or cutting, germ- 
ination can be started, this would be tha 
first step. Such seed as the Ipomoeas, 
Sweet Peas, Cannas, etc., usually come ini 
this group. 
A very common method of pretreating im- 
pervious seed coats is to soak the seed in: 
concentrated sulfuric acid. It is very effect- 
ive with many species, even increasing the 
germination percentage in some cases. 
To treat seed with the acid, of course use 
wood or earthen-ware containers, never 
metal. Merely cover the seed with the 
acid and allow to stand from 15-60 minutes. 
By carefully stirring the mixture the necess- 
ary time required can be reduced. A temp- 
erature of 60-80 degrees F. is best. 
The correct time for this treatment varies 
as to the kind of seed as well as the con- 
dition of the particular batch of seed. {a 
large lots of seeds, small trials can be made 
first with varying time limits and then soak- 
ing the seed in water from 1-15 days, de- 
pending upon the species and then observe 
the number of swelled seeds. Insufficent 
treatment leaves the seed coat on some 
species glossy; too long a treatment pits 
them; correct time leaves the seed dull but 
not deeply pitted. 
After treating, wash the seed with cool 
water for 5-15 minutes. Then carefully dry 
them when they can be held a month or 
more before sowing or they can be immed- 
iately planted without drying. 
Of course great care should be used in 
handling the acid. One important caution: 
do not splash or pour water INTO the acid. 
After treating, pour off excess of acid first 
and then wash. 
Another method is scarification. The seed 
coat is scratched or filed to make an open- 
ing thru the hard seed coat. There are 
mechanical scarifers using sand paper or 
in other cases sand or gravel. 
The January issue will contain lists of 
Roses, Dahlias and Gladiolus. There also 
will be complete listing of Lawn Seeds and 
additional Spring Bulbs. 
DORONICUM - DRABA - DRYAS 
DISPORUM. (dis-POH-rum) FAIRY BELLS. Liliaceae. : 
Perennial plants found in woods and grown in the wild garden. Flowers are solitary 
or in umbels followed by a berried fruit. 
—oreganum. Creamy White fis; 2 ft; HP... essseeseneencseneesenenssseerarecnsnssnssscesenss DISP-6. 20¢ 
DOLICHOS. (DOL-ik-oos) Leguminosae. 
Rapid annual climbers, 10 ft. or more, with Wisteria-like flowers in red or white, fol- 
lowed by attractive pods; dislikes transplanting. All tender annuals. Sow in spring. 
—Lablab. Hyacinth Bean. Fls purple or white, rapid CLIMDET....... csr DOLC-4. 15¢ 
—Soudan. Dark leaves, Purple MOWETS.......ccescccscceeersesseceeeessecscesesenteeseresesenessoneossens DOLC-48. 20¢ 
——Tall Mixed. Purple and white flowers mixed.... Wtwdusessterooee DOLC-4X. 15¢ 
DORONICUM.....(doh-RON-ik-um) LEOPARD’S BAND. Compositae. 
Herbaceous perennials, daisy-like flowers in yellow; blooms early in spring. Prefers 
sun and rich soil. Easily grown. 
—caucasicum. Grows to 2 ft., nice in the DOrder, HP... cecesceseeeeresseeseeeereesses DORO-2. 20¢ 
——magnificum. A more robust type with larger heads; 3 ft; HP.. ...DORO-2M. 25¢ 
—cordifolium. (Columnae) (Ten) Solitary heads; 57; HP... .. DORO-5(F). 50¢ 
—grandiflorum. (Lam) .............. DORO-6(F). 50¢ 
—hirsuium v. glacile. (L) .. . DORO-7(F). 50¢ 
—Blend. All SPECIES MIKE ooe.ceceecesecscesesessreesesessesseesnenssereneessessenssseeeeseseasensensseeasseness DORO-X. 25¢ 
DOUGLASIA. (dug-LASS-ee-uh) Primulaceae. 
—laevigata. Bright red fis; collected 5,000 ft Mt Olympic Mts; HP............... DOUG-3. 30¢ 
—montana. Purple or lilac fis} MOnt; HP .u......0..s..ccccsssssesesscorssrceaseereoceensese DOUG-5. 20¢ 
—sp. nova. Collected at 10,000 ft Bitter Root Mts; ida, HP . 30¢ 
DOWNINGIA. (down-INJ-ee-ah) Lobeliaceae. 
Small plants native to the western Americas. They ere nice in the border. 
—immaculaia. 2-4 in. annual; rich soil; sunny position; HHA............... DOWN-2. 25¢ 
DRABA. (DRAY-buh) Cruciferae. 
Annual, biennial nad perennial plants; flowers are small and dainty, in white, rose, 
yellow or purple in terminal racemes. They are very hardy and popular in rockery. 
—aizoides. Tufted, basal rosettes; yellowish fis; 4 in; HP... .ccesessseeseecees DRAB-1. 30¢ 
—aizoides. Yellowish fls in racemes; tufted; 4 in; HP............ssesesccseseereens DRAB-1(C). 30¢ 
alpina, (1) Fls yellow in’ clusters; Ivs’ basal; 63) Tien liercrreccedonesuseess DRAB-4(F). 50¢ 
—w—glacialis (Fies) Lvs oblong-lanceolate; Siberia; M .. DRAB-4G(F). 50¢ 
DRAB-4P(F). 50¢ 
PLS eC IN) a ecemea teens scare cmecter cree reat aro can ser seostonne veo usnerececeure cases? _ 
. DRAB-10(F). 50¢ 
—athoa. (Boiss) Yellow fis in racemes; 5”; HP... aS 
——nusiriaca.) (facd,, stellata) imVvilke wwihltes VANS EP ik. .c.secssosescossccosnssesecarsuanane> DRAB-1i2(F). 50¢ 
—borealis. (D. C.) White dense corymbose racemes 12”; HP.DRAB-14(F). 50¢ 
—brunifolia. Tufted, 4’; fls pretty orange, racemes; mts Medit; HP.... DRAB-16(F). 50¢ 
—Cirerea. (AGAIMS) erecrcreresecesseressecesscsessesestsseacssessseecssssnesesnsssesentenesnsareneaeneanensass DRAB-21(F). 50¢ 
—diversifolia. (Boiss) Form of D. brunifolia; Armeria; HP.............. DRAB-25(F). 50¢ 
ECL OTTLOT Lye UCU | teteseesee eee ee eee ato sestaaant condone cahrrank-serasyevanuccaseserarvacevacsy . DRAB-26(F). 50¢ 
—elongaia v. balcania. (Sch) .. . DRAB-28(F). 50¢ 
—giabella. (Pursch) . DRAB-30(F). 50¢ 
=— ACTORS Nite diSs) (AR CEIG HS EUS orn cep corarvncraaecteasncessacassansenoransrensseseoortay .. DRAB-40(F). 
—longirosira. Like D. aizoides but smaller; yellow; HP ... t 
Sete clbtiekterh (Glia) oA cots nn rocecenrr cee one coe CED 
—nivalis. (Lil) White, dense racemes, sub-arctic; 3”; HP . 
—norvegica. (Gunn) (D. laxa) White; 8’; sub-arctic; HP f 
—olympica. (Sibth) Large orange fis, compact racemes; Medit; 4°; HP DRAB-51(F). 50¢ 
—olympica. Cushion-like; orange fls in compact racemes; HP.............cc8 DRAB-51. 30¢ 
PED AGHED Ue SLUT) aces oe cree e earn eee arene ro cteedcicdr oceokanuseaatere™ arsuaonenseeas dose . DRAB-53(F). 50¢ 
—polytricha. Yellow fis; dense rosetts; Caucasus; 2 in; HP..........sessssesessee DRAB-52. 30¢ 
—pyrenaica: see Petrocallis pyrenica. 
—sauteri. (Hoppe) 
—siberica. (M. B.) c DRAB-&7(F). 50¢ 
—Draba Blend. All species mixed; this is a RARE blend..... ... DRAB-X, 40¢ 
DRACAENA indivisa: The greenhouse Dracaena — see Cordyline indivisa. 
DRACOCEPHALUM. (dray-koh-SEF-ah-lum) DRAGONHEAD. Labiatae. 
Hardy annual and perennial plants with blue, purple or white flowers in whorls. 
They make pretty groups in most shady spots in the border, where the flowers last long- 
er than when in sun. Easily grown from seed. 
ES FIFALCU SO. SmaI) ebacsece este ace ere aan ceraashasssameceesnveavesoscatten ta cvettsa onicay oma . DRPH-1(F). 50¢ 
—austriacum. (L) Blue fis 14%” long; Caucasus; 18”; .. DRPH-2(F). 50¢ 
—hboiryoides. (Stev) Six inches high; Caucasus; HP... .. DRPH-4(F). 50¢ 
ee [Maireds 9 CRED ie crcev sero eteees cacras seer oaroaascncst scnnentoccaencayere te DRPH-13(F). 50¢ 
DRAB-64(F). 50¢ 
=“Moldavican Charming (border plantsye Wy fits LAC etcccessencancscessdssdtentessesncsenetvevensees DRPH-14. 15¢ 
—tanguticum. Fls blue, 1” long; Mongolia; 2 ft; HP ............ .. DRPH-26(F). 50¢ 
—Wilsonii. (Dunn): Dark blue, clusters; China; 244 £0; HP .....0.....-cccseeoe DAPH-30(F). 50¢ 
—Dracocephelurm, Blenks) All species) ie dy iinsscc--aseectensrssncsteccereenee rte serveursr eer DRPH-X. 30¢ 
DRACUNCULUS. (dray-KUNK-yew-lus) Araceae. 
Tuberous plants native of the Mediterrian regions. Grown in the Soutr or in green- 
houses in the North. 
—vulgaris.Hardy to Long Island in sheltered PoOSition neces DRAK-4. 20¢ 
DRYAS. (DRY-as) Rosaceae. 
Mountain Avans. Dwarf evergreen prostrate plants for rock garden. A very hardy 
perennial for well drained porous soils. 
—Drummondii. (Rich) Yellowish fis; nodding; 18”; 
-integrifolia. (Vahl) White fis, 34” ac: HP 
. DRYA-1(F). 50¢ 
DRYA-2(F). 50¢ 
EPs 
—octopetala. White; 1-112 in. ac; erect; HP... . DRYA-5(C). 30¢ 
ITO LA AMVC Ya CLWial Lic LOLI decscsssesaransnesciensrnsssscersscsscatetoreestateroncsvt csvesnesererteetes DRYA-5M(F). 50¢ 
—Suendermannii. (hort) Hybrid; yellowish to white; nodding; HP........ DRYA-8(F). 50¢ 
OTR DE ireee peste raresceteatenss sores re eteete chars reetcttn tush at ssvase= Se ee icon ere DRYA-9(F). 50¢ 
DEVAS PS LEN Calls COLES ILIKE Op peeerarustenet snnctetcssuresensterctalcadeervetsrcrersrsnesrsextasennre ties ese DRYA-X. 30¢ 
DUCHENSEA. (dew-KEES-nee-ah INDIAN or MOCK STRAWBERRY. Rosaceae. 
Perennial plants from Asia with trailing branches; flowers yellow followed by fruits; 
used as a ground cover or in hanging baskets 4 ; 
—indica. Very decorative; fruits look like straWbeLrrieS}...u.. ce ssssesseees DUCH-l. 25¢ 
ON PURCHASES OF LESS THAN 50¢ WE WILL ACCEPT 3¢ STAMPS 
PIONEER SEED COMPANY ~— DIMONDALE MICHIGAN 
