BOTANICAL AND ECOLOGICAL CHARACTERISTICS
SPECIES: Rubus canadensis | Thornless Blackberry 



GENERAL BOTANICAL CHARACTERISTICS : 
Thornless blackberry is a deciduous, erect or arching, thicket-forming
shrub which grows to 10 feet (2-3 m) in height [3,32,35,36].  The
alternate compound leaves are 4 to 8 inches (10-20 cm) long.  The
numerous flowers are borne in clusters of up to 25.  The fruit is an
aggregate of small drupes, each containing a single hard-pitted nutlet
[3,32].  Rhizomes are typically about 3 to 4 inches (8-10 cm) below the
surface [9].


RAUNKIAER LIFE FORM : 
   Hemicryptophyte


REGENERATION PROCESSES : 
Reproductive versatility is well represented in the Rubus genus [7].
Thornless blackberry reproduces from seeds, by sprouting from rhizomes
and the root crown, and by layering [5].  Vegetative propagation is the
primary source of development of the dense colonies [5,15].  Seeds are
probably dispersed by birds and animals that eat the fruit.
  
Aboveground stems can reach 3 feet (1 m) in height in less than 2 months
[21].  


SITE CHARACTERISTICS : 
Thornless blackberry grows across a wide range of sites throughout the
cool, moist climate of the Northeast [3,32].  It is very common in
woods, old fields, cool hollows, and along roadsides [5,36].

Thornless blackberry is a mid- to high-elevation shrub.  Frequency of
thornless blackberry on heath balds in the Great Smoky Mountains was as
follows [37]:

       Elevation    1200 m     1520 m     1980 m
       Frequency*     17         50         33 

       *average percentage of 6 plots 


SUCCESSIONAL STATUS : 
Facultative Seral Species

Thornless blackberry is shade intolerant [22].  It is present in mature
spruce-fir forests in North Carolina [29], but not in sites undisturbed
for 40 or more years in New Brunswick [9].  It shows vigorous growth in
full sunlight and invades and colonizes many types of disturbed sites
[5,6].  Vegetational changes following the death of Fraser fir (Abies
fraseri) in the Great Smoky Mountains included a large (>10-fold)
increase in thornless blackberry [22].  It is frequent in canopy gaps in
spruce-fir (Picea spp.-Abies spp.) forests of the Great Smoky Mountains
[13,16].  In canopy gaps in American beech (Fagus grandifolia) forest in
the Great Smoky Mountains, thornless blackberry showed 93 percent
frequency on 14 stands [28].


SEASONAL DEVELOPMENT : 
Thornless blackberry flowers from May to June.  Fruits ripen in early
summer and persist into September.  The seed disperses in September
[3,5].

Related categories for Species: Rubus canadensis | Thornless Blackberry