My Dapladenia is outside in the ground. How do I protect it from outside weather?
Growing zone 7 or below, you should bring your Dipladenia indoors to overwinter.
Zone 7 or above you can spread 3 inches of mulch or straw around the roots. Water only when the soil becomes dry and do not fertilize in the winter.
Depending on the region you are in, you are either zone 6b or 7b. If the temperatures in your garden are below 45 degrees F., the plant should be brought indoors.
https://www.gardeningknowhow.com/ornamental/vines/mandevilla/growing-a-dipladenia.htm
My Dipladenia bloomed inside until mid Jan. Now the leaves are turning yellow and dropping off. I don't see any signs of new growth and have not trimmed the plant back or given it any fertilizer. What do I do? Thank you
These need to be fertilized once per month until winter. There are many reasons why these symptoms would happen, but this is the usual culprit.
This article will give you more information on the care of these: https://www.gardeningknowhow.com/ornamental/vines/mandevilla/growing-a-dipladenia.htm
I bought a dipladenia from home depot. When I came home I noticed the tips of some of the stems were brown/yellow/falling off, and it had some brown/yellow leaves. I cut all the dead/yellow/brown off my plant. I was wondering if I killed it, or if it will be ok? The store I got it from had a return policy, so I wondering if I should just go that route. I still have 2 stems in good shape about 8inches long, and the 2inches left from the dead ones I cut back. TIA!
This is the start of a fungal infection, likely, from soil remaining too wet for too long. Make sure that the container has plenty of drainage, and if not, then make sure that it never gets rained into.
Make sure to only water when the top two inches of soil are completely dry. This will prevent infection in the future.
You can add a little wettable sulfur and dolomitic lime to the top of the soil, and it will help correct the issue.
This article will help with the care of these: https://www.gardeningknowhow.com/ornamental/vines/mandevilla/growing-a-dipladenia.htm
What causes the leaves to turn yellow & then fall off. The plants are in pots in a sunny position in Bundaberg.
From the appearance and random pattern of the yellow spots, it appears to be a virus infecting the older leaves. If so, there is no chemical control. Since the new growth appears clear of the disease, the plant may be "out-growing" it. Keep the plant as healthy as possible with good fertility (including micronutrients) and water management.
Viruses are often spread by insect pest vectors, like leaf hoppers and psyllids. Preventive pest management may help prevent spread of the disorder.
I don't know your local issues and resources there on the Sunshine Coast, but check with a local nursery for organic fertilizer and pesticide products.
My Dipladenia is growing long stems and it's time to bring it inside. Can I trim it back?
This article will help you with pruning.
https://www.gardeningknowhow.com/ornamental/vines/mandevilla/prune-mandevilla-vines.htm
We live in Montana near Helena. Will they, the plants, survive and come back after the winter? What should we do? Did we kill them? They were full of blooms when we brought them indoors, Then the leaves started dying on both plants
Cold temperatures can kill them, but it did not likely damage them so much that they cannot be saved. Bringing them indoors can shock them a bit too.
This article will help you to care for these indoors: https://www.gardeningknowhow.com/ornamental/vines/mandevilla/growing-a-dipladenia.htm
I have brought my dipladenia indoors for the winter. It is now shooting vine shoots. Should I cut them off to keep the plant bush?
Technically, yes, it is a vine, but only when there is not enought light. It will seek out more by climbing. It can be kept in a bushier form with trimming, but I wouldn't press pruning too hard over winter.
This article will help: https://www.gardeningknowhow.com/ornamental/vines/mandevilla/growing-a-dipladenia.htm