There was a determination to mix this everblooming characteristic with the cold hardiness of the European roses : albas, gallicas and damasks ( all of which bloom only once a season ).
22.
Endogenous hormone levels are influenced by plant age, cold hardiness, dormancy, and other metabolic conditions; photoperiod, drought, temperature, and other external environmental conditions; and exogenous sources of PGRs, e . g ., externally applied and of rhizospheric origin.
23.
Here you select your geographic zone on the USDA cold hardiness map _ Atlanta's in Zone 7 _ any particular soil situations such as wet, acid or alkaline, and whether the plant will be in full sun, full shade or partial sun.
24.
The designations are given in ranges _ " Z 6-8 " for cold hardiness zones, for example, and " 8-6 " for heat tolerance zones . ( The cold range is always given in increasing numbers; the heat one in decreasing order .)
25.
Dr . Maurice Tauber said, " Even with those insects that don't undergo a classic hibernation, we've learned how to induce cold hardiness and store them for months " so they can be released over a field at the right time to attack an insect pest.
26.
This makes it ideally suited for North American winter weather which often include sudden fluctuations in temperature, and is superior in this regard to its rival for second place in cold hardiness among grapes, " Vitis amurensis ", which is notorious for coming out of hibernation during a warm spell only to be damaged by a sudden frost.
