Wednesday, May 30, 2012

Rose of Sharon Growing Guide

Tips for Growing Althea

Rose of Sharon will help bring a bit of tropical beauty to more temperate climates. The blooms that arrive later in the summer will help revive your garden after the flurry of spring flowers.

Latin name: Hibiscus syriacus

Common Names: Rose of Sharon, Althea, hardy hibiscus

USDA Hardiness Zones: Zones 5-8

Size & Shape of Rose of Sharon: Rose of Sharon grows to approximately 8-12' tall and 6' wide, with a vase shape.

Exposure:  It is best to grow Rose of Sharon in full sun, though it can tolerate up to part shade.

Foliage/ Flowers/Fruit of Rose of Sharon:

Don't be surprised if the leaves arrive after most of your other plants, as they start producing the leaves late in spring. Leaves are 2-4" long, often with 3 lobes, and jagged edges.
The flowers are 2-5" wide, in shades of white, pink, red, blue, purple, and violet. There is often a different spot of color in the middle of the throat.
Close relatives include Cotton. Okra. Mallow. Marsh mallow (marshmellow). Cotton Boll pictured, Left.
Fruit: capsule 

Additional Rose of Sharon Facts:

Rose of Sharon can be VERY invasive due to the numerous seeds produced in the capsules. Snip them off before they open. This causes many to re-bloom! 
Choose one of the newer cultivars that are genetic hybrids - the triploids. These produce few (if any) seed capsules. 
Cultivars  from the U.S. National Arboretum include:
·         'Aphrodite'
·         'Diana'
·         'Helene'
·         'Minerva'

 2 faves are 'Blue Angel' and 'White Angel' 
The blossoms are edible*. (*Colorado State Cooperative Extension Service)
In the UK and Australia, Rose of Sharon refers to Hypericum calycinum, which Americans know as St John's Wort.

Rose of Sharon Design Tips:

Leaves appear late in spring and the blooms do not show until late summer or early fall, so best used in a border, rather than as a specimen plant. 
Rose of Sharon is somewhat tolerant of drought conditions.
Hummingbird magnet. 
Rose of Sharon Growing Tips:
Rose of Sharon grows best in moist, well drained soil that contains lots of organic matter, though happily it is able to tolerate a wide variety of soils.
In the cooler zones (where the temperatures fall below -10F in winter), be sure to mulch around the plant well during the winter season.
With hot summers, Rose of Sharon will thrive, actually preferring the heat, and will increase numbers of blooms.
Propagation is by cuttings and seeds.


Though it is naturally a multi-stemmed shrub, Rose of Sharon can be trained to have a single trunk, looking more like a tree. It can also be trained as an espalier or shaped into a hedge.
Prune as needed to maintain the shape desired. In winter or early spring, last season's growth should be pruned away, which will help produce bigger blooms.

Pests & Diseases of Rose of Sharon:

Unfortunately, Japanese Beetles love the Rose of Sharon shrub. Other pests include aphids and spider mites.
Diseases include leaf spot, blight, and cankers.
The buds may drop if the plant is watered too much or too little, or if too much fertilizer is applied.
Pink Tropical Hibiscus (close relative) is pictured above left. 

Thursday, May 24, 2012

Strawberry Growing Tips

Purchase vigorous starts

Choose early and late bearers to extend the season

Strawberries are perennials for the home gardener, but are treated like annuals in the industry

4 ways to plant: rows, curves, hills or matted bed system

Strawberries thrive in rich soil 

  • plenty of organic material
  • without anthracnose 
  • has not been growing tomatoes, potatoes, eggplants or peppers

Full sun

Mulch- photo is showing plastic and straw mulch on hills at Gwinnett Tech

Water-in and keep moist, since strawberries are shallow-rooted plants 

Topdress with nitrogen

Enjoy the fruit!

Wednesday, May 16, 2012

Native Triumvirate Deliver White Flowers + Brilliant Fall Color

Blue Mist Fothergilla
Pee Wee Dwarf Oakleaf Hydrangea  
Sugartina Summersweet Clethra

Now and then the landscape gardener goes looking for must-have Native shrubs that will fit into smaller scale urban and intown gardens. Leading the pack for fall color are three U.S. natives that also share other characteristics. Crabapple LandscapExperts note:

  • all three plants are North American natives
  • alike in their small, dwarf size and perfect for intown gardens
  • mature  around three feet in height and width
  • all similiar in habitat, growing in sun to partial shade
  • all trouble-free from disease and insect pests
  • all have white flowers, though in very different shapes.
  • all three exhibit long-lasting, brilliant fall color

This selection of low-growing native shrubs are perfect for low hedges, foundation plantings and containers

Blue Mist Fothergilla

This dense compact plant grows 2 to 3 feet tall and wide, and has blue-gray leaves all summer. White, fragrant flowers are produced in spring.

Pee Gee Dwarf Oakleaf Hydrangea

A wonderful native dwarf Oakleaf Hydrangea that matures around 3 feet high and wide, Pee Wee has abundant white flower heads that appear in early to mid-summer, followed by excellent rose to red-purple wine-red fall leaf color, and is a great selection for smaller gardens. Broadly pyramidal inflorescences are delicate, small abundant and almost hide the fertile flowers.

Sugartina™ Summersweet PP21561 Clethra alnifolia ‘Crystaltina’

Dark green foliage perfectly frames the pure white, very fragrant flowers of this dwarf Summersweet. Fall foliage is a warm yellow. This native, low maintenance landscape plant grows 28-30 inches tall and is a butterfly favorite.

Crabapple LandscapExperts enjoy working native shrubs into the landscape when we can. 

Photos courtesy Greenleaf Nursery Company

Wednesday, May 9, 2012

Organic Weed Control

 Crabapple LandscapExperts have noted the demand for alternatives to toxic chemicals to control weeds is rising. Consider two modes of operation: mechanical and common household chemicals. 

Mechanical Methods Organic Weed Control

Apply mulch before the weeds get started
Organic mulches
Wood chips, pine straw, compost
Layers of newspaper
Temporary area: cover with thick opaque plastic for 3 months

Cover soil with clear plastic (painters plastic) to steam-cook weeds
Smooth and level soil, 
Water thoroughly
Causes heat build-up under plastic, and weeds steam cook

Hand pulling/weeding by hand
Slow and steady wins the race
Remove all seed heads (trash, not compost)
Screw driver
Cobra head
Pronged weeding tools

Scuffle or Oscillating Hoe
Warren Hoe
Flaming or Weed Torch
xNot recommended
xBurns off tops but often roots are still alive
xDangerous, burning permit required, not within 50 feet of structures
xYouTube video where house caught fire
√More economical for large areas
xNeed burning training  
xHave hose and shovels ready

Common Home Chemicals Used for Organic Weed Control

Boiling water
Entirely organic with no lingering effects
Boiling water in kettle or coffee carafe with pour spout
Pour slow stream directly on crown of plant
4 hours later look like cooked vegetables
Wear long pants and closed-toe shoes to avoid burning if spilt
May need to repeat if entire taproot has not been scalded

Acetic acid
Full-strength white table vinegar
Spray in small sprayer
Add a few drops of liquid dish soap as a wetting agent
Quick-acting, Non-selective
Can change pH of soil
Later, weeds may re-grow from roots
Some weeds are not susceptible to vinegar (waxy coating, storage roots)

High salinity causes reverse osmosis
Slow but effective
Affects soil, runoff too
Can reverse by flooding with water several times
“Sow the fields with salt” punishment for defeated cities b/c prevents regrowth of plants. Also a symbolic purification of conquered cities

Rubbing Alcohol
Draws water out of cells
Non-selective and will kill your good plants too

Sodium hypocholorite, breaks down to water and salt
Harsher for environment than vinegar

Corn Gluten Meal
Biproduct of corn patented by Iowa State U in 1991
Pre-emergent Seeds sprout then corn gluten meal inhibits roots from growing and young seeds dehydrate
Narrow window of opportunity: timing just as weed seeds are germinating in early spring
Doubles as 10% Nitrogen organic lawn fertilizer

Common Recipe for Organic Weed-Killing Mixture
1 Quart vinegar
1 Cup salt
Few drops liquid dish soap
Hand sprayer
Spray foliage, works best in sun