Oleanders in the yard
I have been overwintering oleanders and other plants along this wall for 20 years, and indeed in makeshift plastic sheeting shelters, built right against the wall, covered only with simple plastic sheeting. It is a south wall, the single large room in the house also serves as an overwintering area for oleanders during the winter and is slightly heated. The wall itself and a large double window thus radiate warmth andsince everything is located in the yard area, it is also sheltered from the wind. When it’s very cold (-10 C to -20 C/ 14 F to -4 F), I also cover the pots with sheeting or towels. When the sun is shining, even with temperatures below freezing (e.g. -5 to -8 C / 18 – 23 F), it can be as warm as 20-25 C (68 – 77 F) inside the plastic shelter. In 2011 I began to make the whole thing more permanent, similar to a solarium – this is what you see now – and in winter, it also gets covered again with plastic sheeting. The lowest temperatures recorded along the plastic-sheet wall of the shelter were -5 C (23 F). in the room -1 to -2 C (28 – 30 F), and on the ground near the wall around 0 C (32 F), plus or minus, or above freezing. Nothing has ever frozen in all these years, nor has there been any frost damage. Early in the spring (April 2012) after the removal of the plastic-sheet walls (the roof was left on as protection against rain), I planted oleanders directly in the ground there (Splendens Giganteum, Mont Blanc, Géant des Batailles/Commandant Barthélémy, 160-170 cm/63-67 inches tall, and 12-15 years old) It is November 17; the marigolds in the foreground have already gotten knocked down by the frost.
Oleanders along the front wall of the house
Both oleander bushes were planted in early summer 2011 ca. 150 cm / 59 inches tall, 8-10 years old). They developed well over the summer and got as big as the narrow frames on the wall indicate. It was to these frames that I attached protective sheeting for the winter; tightly sealed to the wall and lying on the ground. During really cold periods, the two bushes got additional coverings of plastic sheeting inside their shelters.
The oleander on the left is in the protected niche (extra photo), the right-hand one at the corner of the house is unprotected. The house wall is cold. Then, in February 2012 we got three weeks of lingering frost with nighttime temperatures below -20 C (-4 F). The oleander on the left suffered major damage: it lost all its leaves, some of the thinner, younger branches froze and the upper stems froze; the bush had to be cut back to a third of its former size. It has grown new branches during the summer this year, has leafed out again and actually looks quite nice now – just considerably smaller. Of course, there were no flowers at all; it will go into the winter with a large number of latent inflorescences.
The story of the oleander on the right is a short one: it froze to the ground. Dead. I didn’t dug up the rootstock – maybe something would sprout from it – I just put a small oleander, taken out of its pot, on top of it and wrapped it with sheeting so that it could be watered. This rooted into the ground right away and is growing. And then in midsummer, some very small, very thin sprouts appeared from the old rootstock. These, together with the added plant, are forming a small oleander bush.
Will the two survive the winter?
Oleanders planted in the open field
The bush consists of two plants (Splendens Giganteum and Mont Blanc, 160-170 cm/ 63-67 inches tall, 12-15 years old, set out in the spring of 2011) and because of the buried building rubble, they were not planted into the ground, merely taken out of their pots with the rootballs set on the surface of the soil and heaped around with soil. In spite of the not-very-good conditions, they have developed well and went into late autumn bushy, dense, and blooming. As protection, I built them a tentlike plastic-sheeting house and wrapped them with additional sheeting in midwinter. Then, in February 2012 came the three weeks of lingering frost with low temperatures under -20 C (-4 F). The exposed location made the situation worse; there was no additional protection. It was interesting to observe that the ground inside the tent never froze. The oleander bush, however, was killed down to ground level. The protection was simply not enough. The radiation from the sun was too scanty or non-existent for the ground to be warmed enough to be able to store heat. After removing the tent and cutting back the plants to the rootstock, the year began with nothing and the hope that something would sprout.
The photos show that the rootstocks really did start to grow new shoots around June and now the two plants form a beautiful bush about 32 inches high, lush and green, with dense foliage and full of latent flower buds for next year. Light frosts during the night have not as yet been able to cause any damage, in spite of the exposed location.
It’s November 17, the oleander bush remains out in the open. When really cold weather is in the forecast, I will build the protective covering again – and better than in the previous year.