Question
We would like to transplant 2 spirea bushes to a different area in our yard.  I believe they are at least 15 years old. They have a fairly large base.  So I was wondering when is a good time to move them and also how far out from the base and how deep to dig. Thank you!

Answer
Dear Chasity

Thank you for your question.

OK - firstly, be assured that it's very difficult to kill a spirea!  You don't tell me what variety your plants are, but not to worry.  The best time to move most plants is ideally in their dormant season, i.e. when its not in active growth.  Fall is a good time to do this work as the soil is still warm which gives the plants a better chance of putting down new roots than would be the case in winter.

A 15 year old plant will probably be quite big so you will need at least two strong people!  I'll give the pointers in list form - I think this will be easier to follow.  Have a tarpaulin handy - you'll need it to help to move the plant:

1.  Prepare the new planting area - dig a good deep hole for each plant - at least 2 feet deep and the same across.  Of course the size of the plants you are moving will need to be taken into consideration - a bigger plant will need a bigger hole!  Fork over the soil in the bottom of the holes and scatter some all purpose fertilizer into bottom and fork lightly in.  You can also scatter some of the same fertilizer onto the soil from the holes.

2.  Cut off a half to a third of the top growth of the plants to be moved - this makes the plant easier to handle.

3.  The more soil and root ball you can dig out the better, so dig round the plant at least 18 from its base - if the plant is particularly big it may need to be further out.  Dig down as far as you can under the plant getting as much root ball as you can, and then using your spade, sever any roots you cannot dig out.

4.  This is where the tarp comes in - Roll about 2/3 of the tarp up. Rock the plant to one side and place the rolled part of the tarp as far as you can to the underside of the rootball, then rock the plant back the other way onto the unrolled part of the tarp and unroll the rolled part so that the plant rests on the now out-stretched tarp.  Now those very strong people you've 'volunteered' to help will come into their own.  Everybody grab a bit of tarp and lift (or drag) the plant to its new home!

5.  Do the above rock and roll maneuver in reverse!

6.  When the plant is in it new hole start filling around it with the spoil you dug out.  As you back fill the hole firm the soil down from time to time by using your heel around the plant (not too heavily - you don't want to crush the roots, just firm them!)

7.  Once the filling and firming is complete give the plant a very big drink of water to (a) settle the soil and (b) to rehydrate any dried roots.  If the weather is dry water the plant on a regular basis.  

You'll know that your transplant has been successful when you see the first new shoots.  When this will be will, of course, depends on you climate, so it could be a matter of a couple of weeks or not until the following Spring.  All being well you should get many more years of pleasure from your plants!

I know moving a plant using tarp sounds complicated, so you could practice first using a biggish pot plant - you'll be surprised how easy it really is!

Happy digging and good luck