This is the first time I started to winter bare root geraniums. My question concerns the long geranium roots. Can I cut them shorter, and if I do, will it hurt the plants? Will the plants survive when I put them back into the pot or the ground in spring?
If you really want to, you can trim the roots, but don't do so by more than a third. They can survive a root trimming, but it may stunt growth for next year.
Why is my geranium getting yellow leaves on the bottom part of the plant? This beautiful, lush triple plant was on the deck this summer and I want to save it over the winter. It has a sunny spot to be in the house. I suspect overwatering on my part. Also, should I give it fertilizer?
Most likely it is overwatering. Geraniums like to by dry. Water only when the soil is dry to the touch.
I would recommend a slow release fertilizer, like Osmocote, for your houseplants.
I want to know the what varieties of geraniums are most compact and spread out instead of growing tall and spindly.
Many of the Cascade varieties are compact. Other popular compact forms of geraniums include Rozanne, Zonal, and Tango. However, if you are finding it difficult controlling your current geraniums' leggy growth, this article can help: https://www.gardeningknowhow.com/ornamental/flowers/geranium/leggy-geranium.htm
Regular pinching can also encourage a more compact form. This article can help you with that: https://www.gardeningknowhow.com/ornamental/flowers/geranium/pruning-geraniums.htm
I live in El Paso, Texas and last year I had an infestation of whiteflies on my (15) potted geraniums. It was so bad that most of them died. My question is, do I get rid of last year's soil? Do I buy new soil? And what is the best prevention for whiteflies?
I would either get rid of the soil or sterilize it by literally cooking it in your oven at 400 F for 30-45 minutes. This will kill any pests and pathogens in the soil.
Here is more information on controlling whitefly:
https://www.gardeningknowhow.com/plant-problems/pests/insects/whitefly-control.htm
I brought two hanging geranium plants in last fall. They are very leggy. When do I cut them back- in early March or April? I live in northern Ohio.
If you kept them green over the winter, then the best time to prune them was before you brought them in. But, they can still be pruned in March and be just fine. Here is more information: https://www.gardeningknowhow.com/ornamental/flowers/geranium/pruning-geraniums.htm
I planted geraniums in spots on the grounds - they look fantastic. Will they last indefinitely? They can be covered if there is a frost warning. Thanks
Geraniums will live for many years, but they do tend to get woody and leggy as time passes. You can help hold this off with regular pruning. These articles will help you with keeping that from happening:
https://www.gardeningknowhow.com/ornamental/flowers/geranium/pruning-geraniums.htm
https://www.gardeningknowhow.com/ornamental/flowers/geranium/leggy-geranium.htm
I have a geranium that is gonna die. It wilted. What can I do to save it?
Geraniums are pretty tough. As long as the main stem is still alive, it will regrow its leaves. Give it proper geranium care in terms of watering and light and it will come back. This article will help you tell if the main stem is alive:
https://www.gardeningknowhow.com/plant-problems/environmental/how-to-tell-if-a-plant-is-dead-and-how-to-recover-an-almost-dead-plant.htm