Gelsemium sempervirens, or Carolina yellow jasmine, is a hardy evergreen...

Gelsemium sempervirens, or Carolina yellow jasmine, is a hardy evergreen vine that survives winters on Long Island. Credit: Missouri Botanical Garden

I enjoy your garden column very much and look forward to it on the weekends. In your column on May 9, you referred to your dog Maddie severing a jasmine vine that was growing on a trellis. I assumed that the jasmine was planted on Long Island in the ground. If this is the case, how do you protect it for the winter? I have two jasmines that I drag in out of the weather, but I nearly lost one this year. I really would like to leave them outdoors if that is possible.--Al Arnedos, Wantagh

My vine, the yellow-flowered Carolina jasmine, belonged to the genus Gelsemium, an evergreen that's hardy to zone 7, so it survived winters on Long Island better than it survived Maddie. I suspect you're growing a species of the Jasminum genus, perhaps pink jasmine, or one from the Trachelospermum genus, like white jasmine. Those are tropical vines that cannot overwinter outdoors on Long Island. This is a perfect example of the importance of using botanical names to identify plants rather than common names, which can be shared by many different plants. If you're looking to replace your vines with hardy jasmines, you might consider the Gelsemium I grew or Jasminum nudiflorum Lindl, winter jasmine, which you'll be able to plant in the ground.

Can you think of any reason why my lilacs have never bloomed? I cut them from a mature, 40-plus-year-old plant three or four years ago. I rooted them in pots and then planted them in the ground, where they have both flourished and grown. One is about 5 feet tall now; the other not so large, but healthy, with new growth every year. They both get a mix of sun and shade. Is there something else they need?--Doug Ward, Lindenhurst

New lilacs grown from cuttings usually won't bloom for two or three years, so it could be that yours are just a little behind. Also, they need at least six hours of full sun each day to bloom properly, so your shade could be a contributing factor. And if you pruned them after July last year, you probably removed buds that would have been this year's flowers. Give them a dose of phosphorus in early September and again in early spring - before they would bloom - to help things along.

My upside-down tomato plant has many yellow flowering buds. Should I thin these out or let them be? Your response is greatly appreciated. Many thanks and have a glorious harvest. --Helen Shack

Let them be, Helen. Removing the buds would mean fewer tomatoes.

Please let me know the best time to split hostas.--Maureen Pisano, Lindenhurst

Anytime, Maureen. Hostas are the toughest plants known to man.