- Spring Care for Boxwood
- Question of the Week
- 'Apricot Sparkles' Daylily

Boxwood, especially Dwarf English Boxwood (Buxus Sempervirens Suffruiticosa), are subject to several ailments that all evidence themselves similarly.  Winter damage, Phytophthora (root rot), and microscopic root-feeding worms, called Nematodes, all show up as whole branches that first turn bronzy green, then copper-color, finally lightening to a straw color as the branch dies.  Without expensive scientific study, often it is impossible for the homeowner to determine whether or not damage was caused by nematodes or root rot.  But, no matter.  Neither can be cured with any pesticide available to the homeowner, but it is possible to suppress the spread of both nematodes and phytophthora with organic treatments that provide good growing conditions.  Additionally, boxwood that is growing under healthy conditions is less likely to suffer winter damage.

A Spring Tonic for Boxwood

• Remove existing mulch being careful not to disturb the roots.

• Apply one handful of Kelp Meal for every foot of plant height. (This presumes your boxwood is as tall as it is wide.  For boxwoods that are tall and thin, use less.  For those that are short and broad, use more.)

• Apply two handfuls of Plant-Tone^®  or fertileGro™ fertilizer for every foot of plant height.

• Cover the entire root structure from the trunk to the outside of the root mass with one inch of Chesapeake Blue crab compost or top dress with Neptune’s Harvest crab shell.
  (Crab shells contain chitin, which increases populations of natural, beneficial chitin-feeding microbes in the soil.  When the microbes have consumed the chitin in the crab, they then consume nematodes - eggs & adults - which are also composed of chitin.)

• Cover with two inches of PINE mulch.  (Only pine mulch has been shown to suppress root rot.)

microphylla Winter Gem

microphylla True Spreader

We do not recommend fall feeding of boxwood.  We also do not recommend Holly-Tone^® or Cotton Seed Meal as they are for plants that prefer acid soil.  Boxwood prefers a slightly alkaline soil.  Chemical fertilizer should never be used on boxwood.

Boxwood at Carroll Gardens: 
Green Ice  |  microphylla True Spreader  | m. Winter Gem | Dwarf English Boxwood

More info: 
Kelp Meal  |  Plant-Tone®  |  fertileGro™ 
  Chesapeake Blue  |  Neptune's Harvest Crab Shell

Question of the Week

Question
I have a big maple tree in the back of my yard and grass just won’t grow there.  In some places the roots are raised well above the soil.  It’s a real ankle tripper.  I’d like to have something green and low-growing there.  Is there a possibility that anything more interesting than ivy that will grow there?  Should I bring in top soil to cover those roots?  Should I have the tree topped?

Answer
First the tree.  I recommend topping trees in only the rarest of instances; it ruins the structure of the tree.  Obviously more light will help your plants grow better.  Why don’t you consider having the tree thinned?  Maybe you can let more light in from the sides by having the bottom branches removed.

If you decide to add more top soil, you can only add 1-2 inches without suffocating the roots on the tree.  Even if you add soil, you can’t put the plants in the new soil.  They must be rooted into the existing layer of soil to survive. 

In general, the plants and surrounding mulch will pretty much conceal the exposed roots.  So, I don’t think you’ll gain much from adding top soil.  Try and plant between the big roots; that is, amongst the fibrous roots.  For each plant you’ll probably have to chop out (with an ax) a one foot square section of soil and replace with a mixture of ½ top soil and ½ Leaf-gro and a handful each of Kelp Meal and Cotton Seed Meal mixed in.  In moderation, this chopping process will not harm the tree.  If you want more coverage than you dare to disturb the tree roots, either choose plants that spread naturally or come back in a year or so and do more planting.  You need to water each plant with a root stimulator such as Sea Mate.  You should water thoroughly every other day for the first season.  Next year you can probably get by with weekly watering, and after that watering will only be required in periods of greatest drought. 

We have in our online catalog a collection of plants for dry shade.  Dense, dry shade, as you describe, is the most difficult of all gardening conditions. 

• I have had good luck with Sweet Box (Sarcococca), which is a dwarf evergreen that spreads slowly underground.  It has shiny dark green leaves and fragrant white flowers in early spring. 

• Lenten Rose (Helleborus orientalis) is also evergreen and blooms in early spring.  It may even generate young seedlings in your garden. 

• Geranium macrorrhizum is semi-evergreen and blooms in late spring and, depending on the variety you choose, comes in shades from almost white to deep pink.  These geraniums will spread slowly into large masses.   

• Another slow spreading plant, although somewhat taller, at 2 feet, is Variegated Japanese Solomon’s Seal (Polygonatum odoratum Thunbergii Variegatum).  It has arching stems with little white bells in the spring.  The variegated foliage is handsome all season. 

• One species of Coral Bells (Heuchera villosa) will persist as long as the shade is not too dense.  The variety Purpurea has red leaves and the variety Autumn Bride has particularly handsome white flowers with lettuce green leaves.  The villosa Purpurea was selected by my friends at Rock Knoll Nursery in Ohio and the villosa Autumn Bride at Bluemount Nursery in Maryland.

• Yellow comfrey (Symphytum) also persists in very dry shady places.  It has tiny lemon yellow bells in spring that arise from a mound of dark green foliage that remains handsome all season. 

• Two varieties of Archangel (Lamiastrum) will thrive in your conditions.  Both have masses of soft yellow blooms in the spring.  Variegatum is a fast spreading ground cover with green and silver foliage.  Herman’s Pride doesn’t spread. It remains a clump; the leaves are smaller but with even more silver on them.

• One final choice, yellow Bishops Hat (Epimedium veriscolor sulphureum) also has pastel yellow blooms in early spring.  It grows about a foot tall and makes a tight mound of light green foliage, beautifully accented in spring with maroon.

Incidentally, most, but not all, of these plants are deer-resistant, please refer to the newsletters from April 11th and 17th for more details.

As you can see there are many more choices than you may have realized there was.  I suggest you experiment with a little of this and a little of that and see what does best in your specific conditions.   
 

Featured Plant - 'Apricot Sparkles' Daylily

This ever-blooming dwarf is deep apricot in color, with a marvelous sparkling quality to its petals. A grandchild of 'Stella D'Oro' and 'Brocaded Gown', Apricot Sparkles starts to bloom very early and continues until frost.

Hydridizer Dr. Darrell Apps says its blooming power is greater than any daylily he has ever developed. Apricot Sparkles produces blooms over 4" wide. The scape height of this daylily is about 15".

Carroll Gardens is pleased to introduce  'Apricot Sparkles' to our 2003 online catalog!  Click here for more details or to place an order.

I hope this newsletter has provided you with some greater insight with respect to spring care for boxwood, as well as the other topics covered. As always, I welcome any feedback or comments you may have.

Happy Gardening,

Alan Summers