Horticulture Guy"Live Long and Garden" – Peter Punzi

Q.  We have a long low laurel hedge that is set about 10 feet too far into the property and we’d very much like to move it further out. I know laurels are pretty forgiving of pruning, but can they survive being moved?   At what time of the year would be best, and how would we best go about it? How much of the root structure is needed? Does one prune it right after? Does it need fertilizer etc.  Thanks so much! Virginia Keyton – West Vancouver, BC

A.  This all depends on how long the hedges have been in place and how big they have become.  When I moved into my house I had a 30-foot tall 15-foot wide hedge along a property line leading up to the side of the house that made the house look Lilliputian.  My goal was to remove them so I cut them down with a chain saw and tried to remove them with a maul.  I quickly found out just how hard their wood is.  I wore down a few blades and had to enlist the help of a backhoe to remove them.  A friend wanted to try and salvage the large root systems I wrenched from the ground and planted them on their property without success.  This of course is an extreme case and my intentions were removal and not saving the shrubs.  I think if they are not that large you will be able to move them without incindent.  Since they are evergreen I would suggest moving them in the fall just before the rainy season kicks in.  I know this doesn’t help for this fall but root-pruning a year in advance would also help their transition.  The more root system you can maintain during the transplanting process the better the chances are for the tree’s survival.  At some point you will have to determine if it is worth the work since you could plant a new hedge and they would grow in quite quickly. 

Q. I had mildew on my peonies for the first time this year. The phlox have it every year but never the peonies. What would cause it? Thanks Marilyn Dowson – Canada

A. I bet you are wondering if the disease spread from your phlox to your peonies.  It is doubtful.  The mildew you are referring to is powdery mildew to which most phlox are highly susceptible.  Powdery Mildew is a common name used to refer to many different pathogenic fungi that attack ornamental and crop plants and appear as a white cast on the surface of leaves.  In the case of phlox the species is Erysiphe cichoracearum .  As a general rule different species of Powdery Mildew have very specific hosts and a few have a larger host range. Although Erysiphe cichoracearum has a relatively large host range the hosts are considered limited to plants in the Aster Family (Asteraceae/Compositae) (e.g. chrysanthemum, dahlias, phlox, sunflowers and zinnia).  A probable scenario is that your peonies have another fungal disease called botrytis (Botrytis cinerea) or grey mold.  If you find infection of the flowers then this is a good indication of a botrytis infection.  Both fungal diseases are exacerbated by lack of air circulation and humid conditions.  The fungal spores need some moisture present on the surface of the plant to germinate and grow.  It could be from overhead watering or even from dew that forms overnight and doesn’t evaporate due to poor air circulation.  So anything you can due to change the environmental conditions will help.  Sanitation (removal) of infected leaves is also helpful since you reduce the spores available next season.   Both diseases can be controlled with copper based fungicides.

Q. How do you propagate Dizygotheca elegantissima and will it branch if the tip is snipped? Nancy Bandusena – Kota Kinabalu, Malaysia

A. Well I am sure where you live you can grow the False Aralia (D. elegantissima) as an outdoor landscape plant since you are in a tropical climate but here in the Pacific Northwest we know it as a house or sunroom plant. The False Aralia had a heyday during the Victorian era as a conservatory plant. It has since been used occasionally in indoor landscaping and as a houseplant. Despite being having beautiful light and airy foliage with coppery cast this plant is finicky when it comes to warmth and humidity. Lack of warmth and humidity will cause the lower leaves to drop. This detracts from their inherent beauty. The False Aralia is reluctant to branch even when cut back so it is difficult to force new foliage below. They can be propagated by seeds (if your plant produces any) cuttings, and air layering. So if a plant is getting leggy you could air layer the plants (making a cut part way through the stem, putting rooting powder, wrapping inside the wound and outside with moist sphagnum moss and then wrap with plastic) to shorten up the plant. Once roots have formed you can cut below the layer and replant all the cuttings. Or Take cuttings using BONTONE ROOTING POWDER..