I have 2 new passionfruit vines and both are under attack from pests that are not visible. The new leaves are being eaten, and now the older leaves are also showing results of something chewing away at them. Without being able to identify the pest, is there a home made non-toxic spray that might protect the plants from total eradication ?
If you are seeing night time damage with no visible pest, it is typically slugs or snails. They do like new growth best and will move on to older growth when new growth is gone. These articles will help you:
https://www.gardeningknowhow.com/plant-problems/pests/facts-about-slugs-and-how-to-kill-garden-slugs.htm
https://www.gardeningknowhow.com/plant-problems/pests/organic-snail-control-how-to-control-garden-snails.htm
I have some blue passion flower plants that I planted in the ground, and now it is winter time and I did not bring them indoors. I would like to know if they will survive the winter in the Toronto area? I would also like to know if I can leave the dahlia tubers outdoors as well?
As for the dahlias, these will need to be dug up and stored. They cannot survive winters in your area. They can be easily lifted with a garden fork or spade shovel prior to the complete die out of their foliage. Break up the clumps and separate the tubers, allowing them to dry out some before storing, usually about a week or two in a cool, dry area.
Then, clip off foliage, shake off any remaining soil, and pack the tubers in dry peat moss or wood shavings within a brown paper bag or cardboard box. Place them in a dark area with cool room temperatures, like a basement, until spring.
While it's often better to grow passion flower in a container that can be overwintered indoors, it is possible to grow the plants outside. In cold regions such as yours, extra protection should be taken, especially passion flower, which is happier in warmer areas. The following article should be of some help to you:
https://www.gardeningknowhow.com/ornamental/vines/passion-flower/preparing-a-passion-flower-vine-for-winter.htm
It was started from a cutting in October and doing well, lots of new growth. Two days ago the top leaves were looking very wilted. Now more of the top of the vine is collapsing. The plant is about 10 inches tall and is in the house for the winter. I believe it is a passion incarnta. (sp)
It sounds like it is either over watered, under watered or has root rot. Check the roots for root rot. This article will help:
https://www.gardeningknowhow.com/plant-problems/disease/treating-root-rot-gardening-tips-for-housplants.htm
Make sure the soil is draining well and that you are not letting it dry out in between waterings.
I live in south central Texas and my passion vine has been beaten up by the unusal frigid, consecutive, below-freezing days. It has been growing up our covered pergola porch for about two years, but now ALL of the vines have dropped leaves and look dead. Do I take all the vines off the roof and prune it back? If so, how much and when should I do this?
I would wait until spring to cut back the plant. It will help protect the new growth, just in case another freeze occurs. But, it will need to be pruned in the spring. These articles will help you:
https://www.gardeningknowhow.com/plant-problems/environmental/how-to-tell-if-a-plant-is-dead-and-how-to-recover-an-almost-dead-plant.htm
https://www.gardeningknowhow.com/plant-problems/environmental/tips-for-saving-cold-damaged-plants.htm
I'm thinking of buying a passion flower plant. I can only do container plants because of where I live. My question is, can this be grown as a hanging plant without a trellis?
Yes, you can. Here is more information about growing these plants: https://www.gardeningknowhow.com/ornamental/vines/passion-flower/the-passion-flower-a-perfect-tropical-vine-for-growing-indoors.htm
My outdoor passion flowers froze in the Florida freezing temps. Will they grow back?
Maybe, it depends on how deeply the cold went. This article will help: https://www.gardeningknowhow.com/plant-problems/environmental/tips-for-saving-cold-damaged-plants.htm
We have a passion vine that was covering two small, dead trees. We removed the dead trees and now have the vine with the dried up leaves on the ground. How much can we prune back on the vine to ensure good regrowth?
I would cut back by a 1/3 and see how the plant fairs with that. After it grows some, you can do 1/3 again.