Hi all- I've been meaning to transplant some hollyhock after I got it ID'd from davesgarden. Now I really don't want to kill them, so is there anything I should know about when to transplant or how much I should water them...
I'd wait until fall for transplanting anything--that's a great time of year to plant/transplant things out here. That way they get cooler weather and then the winter rains to help them establish. If you can't do it then, late winter/early spring would be the next best time, but fall is really the #1 time for doing things like that, I've been amazed how much better things do when I plant them then vs any other time of year. Summer is the absolute worst time so I definitely wouldn't do it now. I mostly deal with shrubs and evergreen perennials though, I know hollyhocks die back in the winter so I'm not sure if that changes when it's good to transplant them, obviously you should dig them up before they die back, otherwise you won't know where the plant is! It's also possible that the hollyhock may not survive the transplant if it bloomed this year--they're supposed to be biennials and die after they bloom, and although mine usually behave as perennials here, if you pick it up and transplant it when it's in theory supposed to be dying anyway, then it may decide not come back for you. Or it might, you never know with these things. But I'd probably save some seeds from it just in case.
Best time to transplant any plant is when it goes into dormancy or just as it awakens from it, so you should dig it up when ALL the foliage has died off, or shrivelled and you know it is time to chop the foliage away, chop before you dig it up. These have a good big root system so dont be faint hearted, remove as much soil as you can with the roots, take it to new site, have the new hole already prepared and add some plant feed to the hole and soil, give the soil/hole a good watering and plant the Hollyhock into the hole, firm gently with your foot as these plants need firm earth so they dont fall over as they grow taller. When you get the plant dug up, have a look at the roots and see if there are any root cuttings you can take, these are little bits of new plant growing from the roots, if there are some and they have a bit of root attached to them, cut them away with a sharp knife and keep them in a little pot under protection so they will grow on over the winter, then you can plant them outside in the spring, all they need is to make new roots over the winter and you have some more new Hollyhocks for free. Good Luck, WeeNel.
I've been postponing transplanting my hollyhocks because I don't want them to die off. I always cut the flower stalks down as soon as the blooms are done, and they don't seem to know that they're biennials. However, the base clump has gone from the original 4" single base to a 3' clump of connected plantlets and is starting to choke out the surrounding plants. I'm going to divide and transplant in the winter, and hope for the best.
The University of Colorado had this advice: Transplanting is best done in the spring taking care to avoid plant damage. The roots are large and the growth is from a few strong buds at the crown. If planted in the fall in areas where frost heaving is a problem the plants may heave out of the ground and plant death may result. Applying a three to four inch layer of mulch over the plants after the ground has frozen in the fall will help reduce this problem.