I think it is so sad that we gardeners must leave our beloved gardens to go to other places during the growing season. But even I, confirmed gardening addict, love to travel and sometimes summer is the only time for certain ventures. This year my husband and I will be going to Rzeszow Poland to teach in an English immersion program for part of July. What about the gardens? Before leaving, I follow a certain ritual. First I take pictures of the gardens. This is so I can remember their beauty later in the season. I deeply water all plants in the garden that would benefit from such treatment. I deadhead the perennials. I actually pinch or cut off all the flowers from the annuals. If the annuals look leggy I cut them back to lessen the chance that they will go to seed during our absence. I remember a day in the summer of 2003 waiting for my husband to take a relative home the day before we were to travel so I could dash about and cut back all the annuals. When we returned after three weeks they were magnificent!
I thoroughly water our houseplants as well. I have a trusted person (my sister) check on them when we are away. If you do this remember your house watcher doesn't want to kill your plants so give him/her careful written instructions. If your plants were in good condition when you left they will probably survive your absence just fine. If not make cuttings from them when you return home. (I am assuming they will still be alive.)
Don't forget your container gardens! If your plants are already growing in compost, potting mix, a slow release fertilizer, and water retention granules, you already have a step up toward their continuing success. Perhaps you could ask a trusted neighbor to check on them daily. (I will never forget having our youngest daughter and spouse take care of the hanging baskets on our front porch. We returned from our travels late one night and noticed that the hanging baskets were dripping water. We looked at the baskets the next day during the daytime. They were the deadest crispest plants you could ever imagine.... but they were wet. Everyone is not plant folk.)
Enjoy your travels. Hopefully little or nothing will die in your absence. And just think of all the fun you will have gardening upon your return.
On another note.....I received a question about a plant and the reader later sent it to me for identification. It was daisy fleabane. The reader asked if it was a weed or a garden flower. I smiled. This plant is a source of discussion at our house. Five years ago I was in the hospital during spring garden cleanup time. When I came home my husband said the gardens looked so beautiful even though I had been unable to work outside. We went outside and there in the perennial beds were scores of plants with daisy like flowers, some over five feet tall. I knew I had not planted them! Jim said they were so pretty! As my health improved I returned to my gardening ways and tried to eradicate them from the garden by pulling them out.
In western New York State there are two species of daisy fleabane, one an annual, the other a biennial. The annual fleabane has alternate toothed leaves. The flowers are white. The other fleabane, a biennial, is Philadelphia fleabane . The leaves are also alternate but they grasp the stem. The flowers are pinkish or white with yellow disc flowers. I try to keep these plants out of the garden by pulling them out early in the season but every once in a while one sneaks past me and blooms! Yes I think it is a weed because it seeds everywhere but then so do many of the planted species in the garden. Just don't ask my husband about this. He will say "They are so beautiful."