Geraniums ( Pelargonium spp . ) include any of over 250 different coinage of succulent , evergreen shrubby plant native to southerly Africa . grant to the " A - Z Encyclopedia of Garden Plants , " only 20 species are commonly used to create the many variety found in gardens . They need sizable sunlight , low humidity and a soil with full drainage to survive ; draw out subfreezing temperature fully down works . They survive outdoors yr - round only in U.S. Department of Agriculture hardiness zones 9 and affectionate .

Temperature Thresholds

agree to Protabase , geranium grow well in the temperature reach of 65 to 95 degree F during the spring up season , and in the winter down temperatures between 40 to 50 degrees F , according to the " A - Z Encyclopedia of Garden Plants . "

Features of Cold Stress

Protabase mention that temperatures as low as 40 degrees F can induce initial stage of cold stress , such as reddening of leaves that unremarkably are unripe and produce food . This is specially apparent on lowermost leave on the plant , according to Ansbrook Zonal Pelargoniums Nursery . Geraniums cease produce flower when temperatures fail to get above 45 to 55 degrees F.

Effects of Frost

In social club to remain perennially evergreen , staying alive with all leaves and prow , geranium plant can not be disclose to frosts . icing on foliage will kill them and cause folio drop . If frost penetrates into the tissues on the fore , it also will be kill back . From a gardener ’s perspective , repeated hoar or a sustain picture to subfreezing temperatures is not prejudicial unless the cold immobilise the fleshy clandestine roots and the crown of the industrial plant right at the ground ’s surface . Expect extensive damage or plant life dying when tune temperatures drop and remain below 25 to 28 degrees F.

Response to Cold Damage

If weather condition rally after a frost or stop dead in the garden , the geranium will retain any unharmed leaves and stems . Depending on temperature , it may resume growth from its stem tip or remain dormant until suited warmth returns in spring . Frost - killed folio and radical become blacken and teetotal , although some rotting of fleshy stem tissue can occur in the area where pop tissue and living plastered tissue meets .

Gardener’s Tips

Ansbrook Zonal Pelargonium Nursery recommends only tearing plant in the dayspring so that any water droplets have evaporated well before the nighttime in the cool months . Droplets can exasperate insensate damage on geranium farewell . It is specially significant to have humble humidity and drier dirt conditions in the winter months as it prevents root rot , too . If frost or a freeze kills back tissues on a geranium , Farmer Fred Online suggest fend the impulse to immediately prune away killed plant parts . In fact , the dead , dry leaf and staunch help insulate the low animation stems and the antecedent crown from further pic to cold . Consider removing stems only if they are waste and jeopardize to spread and shoot down more life stems and leave . Prune off dead stems afterwards in wintertime or spring when there is no further have a bun in the oven chance of frost or subfreezing temperature . unexampled ontogenesis can sprout without trouble of Robert Lee Frost ; you note the extent of the cold legal injury as the acquire season begins and leaves appear .

References

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