They need drainage. If the pot dries out badly or is exposed to lots of sun/wind it will drop the lower leaves. You're saying quart, meaning 1 gallon pot? (not liquid measurement-approx 6" dia.)
They likely need to go into 3 gallon pots.
kevin

Actually, oleanders (especially potted), can't take wet feet. That will definitely take them down. I let mine dry out well before watering again.

When you say "plant", are you talking about planting out? If so, they are only marginal in as far north as Zone 8 with protection, but since you do cold hardy palms, I expect you are going to make a go at it anyway. ;-) Good luck if so.

CoolPlants - the "quart" pots are like 4" pots. I got my oleander in that size (12" cutting) several years ago, then moved to 8", and its now in a 12" (about a 5 gallon equivalent).

These aren't just any oleander, such as typical red and salmon. I purchased mine from plant delights nursery in Raleigh/Durham, North Carolina. They are rated to a zone 7b ( I realize they will require some protection), but apparently the owner of the nursery said he collected seeds from a variety that survived the "freeze from hell" back in the 1980's, when temperatures in Raleigh fell to -9F. He said they will burn to the ground in subzero weather, but they have never had any problems with root hardiness. The leaves usually burn in the single digits, but I think I can keep the old wood alive.

I figure their worth a try. Their beautiful, and evergreen is always good!

Thanks, Zach

I have heard about those. Sounded interesting too! Wish you luck with them. :-)

Thanks! If I have any luck over next winter, I'll post a report next year!

Zach

Sounds like overwatering. Oleanders like hot, sunny, dry conditions. They're native to Arabia, and they grow well along the freeways of southern California. My guess is that you have been keeping yours too wet. Try letting them really dry out before watering and give them as much sun as possible.

I should let them dry-out, even as seedlings?...Now I really like this plant!...lol :)

Yep... even as seedlings. When you see the leaves are starting to get just the hint of softness just before drooping - then water. LOL When you do that, the leaves will become turgid again.

I had a cultivar "Hawaii" that unfortunately stayed too wet the beginning of last summer due to all the rain and overcast we had and it eventually bought the farm.

I agree, the only time I've seen yellow leaves on an oleader was after one of our tropical storms that hung around and dumped rain for weeks. Almost every oleander in town had some yellow leaves. I don't even water the cuttings when I do them. Didn't know you could kill these. We watched my brothers neighbor pull the bumper off his truck trying to pull one out of the ground. Still laugh when we see him. Tally Ho!

Yes excess cold water will cause some yellowing, that is typical of winter weather here in Sacramento and that is when the leaves yellow and fall off, but the old Western Garden Book lists them as plant that will thrive in both wet and dry conditions so water is unlikely to kill them. If conditions are warm they love water.

they may be shedding their old leaves, my oleaders do that in every early summer before they bloom.

My oleanders (about 1 year old now) are dropping yellow leaves. I live in Central West Florida - it is hot, humid and extremely dry and we can only water once a week due to restrictions so over-watering is not a possibility here. They are in full sun most of the day .. Wonder why the leaves are yellowing and dropping..

Lucy, I'd say overwatering, but you say that's not possible. Then again, you say you water once a week. Are Olearnder growing in pots or ground? Soil should dry out thoroughly before adding more.
Have you checked for insects? When bugs are present, leaves can yellow. Toni