Getting More Out of Your Ground Cover Plants

I have a very long strip of landscaping area between my lawn and the cul-de-sac, with six different types of plants growing (see photos below). I want to propagate those plants to make many more and fill in the area. In this article I will give the basic principles of propagation used for ground cover plants grown in this area.

Crown Division, or Division Division is form of plant propagation where new plants are not grown from seeds or bulbs but are separated from the parent plant. The crown of a plant is where its stem meets the roots.

• Carefully lift plant clumps along with some soil removed from the roots.

• The crown may then be cut into sections with a knife.

• Individual growing points (shoots) that contain roots may be used to form new plants, or if a larger plant is desired, several shoots may be left together.

• When dividing large, old crowns, it is often best to discard the older, center portions and replant the young, more vigorous shoots that have developed on the edges of the clump.                                                   

Stem Cuttings A stem cutting includes a piece of stem plus any attached leaves or buds, so it only needs to form new roots to become a plant.

• Cuttings should be 4 to 6 inches in length and taken from vigorous, healthy plants.

• Remove the cutting from the mother plant with a sharp, clean knife.

• Use a rooting hormone.

• Cuttings should be placed (stuck) in a propagation medium that retains moisture, yet is porous. Do not allow the medium to dry out.                          

Leaf cuttings
A leaf cutting uses just the leaf for propagation, so both new roots and new stems must be formed to create a new plant. Leaf cuttings first must form roots and later shoots. Depending upon the species, it can take several months to produce a plant suitable for transplanting from a leaf cutting.

• Remove only a leaf blade or the blade and a portion of the petiole.

• Apply rooting hormone, and sink the petiole into the rooting mix.

• The base of the leaf blade should just touch the mix.

• Place the pot in a plastic bag in a bright spot.

Root cuttings Though very few plants can be propagated from root cuttings, the technique is simple. 

• When the plant is dormant, dig it up and cut off robust segments of the root, 2-3 inches long. 

• If the roots are thin, lay them horizontally on the rooting mix and cover with 1/2 inch of the damp mix. If the roots are thick, lay them horizontally or place them vertically into the rooting mix, covering them completely. If placing the root vertically, make sure the end of the cutting that was nearest the crown of the plant points up. 

• Put the pot in a plastic bag and place in a bright spot. In several weeks, shoots should emerge from the rooting mix. Keep the pot in the plastic bag until new roots have formed on the shoots.   

The chart below shows some of the common ground cover plants grown in the Treasure Valley of Idaho.

Common Name	Scientific Name	Best Ways to Propagate
Stonecrop	Sedum spurium	Division
Periwinkle	Vinca minor	Division
Mazus	Mazus reptans	Rooting at the nods
Creeping thyme	Thymus serpyllum	Division, seeds or cuttings
White Woodruff	Golium odorstum	Self-seeds
Lamb’s Ear	Stachys bysantina	Self-seeds profusely
Houseleek / Hen & Chicks	Sempervivum tectorum	Leaf cuttings
Moss Phlox	Phlox subulata	Division, stem/root cuttings
Prickly Pear	Opuntia macrorhiza	Stem cuttings
Snow-in-Winter	Ceratium tomentosum	Self-seeding, division
Rockcress	Arabis caucasica	Seed, division/stem cutting
Candytuft	Iberis sempervirens	Division, or stem cuttings
Basket-of-gold	Aurinia saxatilis	Self-seeds, or direct seeds
Bearberry Cotoneaster	Cotoneaster danneri	Stem cuttings
Silver Mound	Artemisia schmidtana	Division every 2-3 years
Rose Moss / Purslane	Portulaca grandiflora	Cuttings
Ajuga	Ajuga reptans	Seed or division

Bees–Wasps –What’s all the Buzz?

Many creatures (seen and unseen) call Southern Idaho backyards home. For many of us, our introduction to flying yellow and black insects was an unwelcome and painful sting. Through experience and education, we know that some of these flying creatures are more friendly and less aggressive than others. 

Identifying the subtle differences between each species is not always intuitive–but important. It’s not as simple as identifying good vs. bad or friend vs. foe. Understanding each species can help us manage a safe and healthy backyard ecosystem. 

Bees – While there are 25,000 different species of bees, SW Idaho is home to more than 400 native bee species as well as some introduced species, such as the European honeybee and the alfalfa leaf cutting bee.  While it may be obvious, only honeybees (not native to Idaho) generate honey. The most common bees are worker bees who collect pollen to feed the queen and support the hive.  Bees also perform the important job of pollinating our gardens and fruit trees.  While generally less aggressive than wasps, bees can and will sting. 

Wasps – While known by many other names (hornets, bald faced hornets, yellow jackets, etc.) all are technically wasps. There are 30,000 wasp species. They can be recognized by their pointed lower abdomen (not furry), narrow waist, and shiny, slender cylindrical shaped legs. All wasps hunt food and build nests. Adult wasps cannot eat solid food. They return solid food (other insects, meat, fruits, etc.) to the nest to nourish carnivorous larva. The larvae digest the solid food and emit a sugary waste substance which is a primary food source for adult wasps.

There are two general wasp classifications, social and solitary.  Social wasps work together to build nests. This process begins from scratch each spring; they never return to the old nest. Adult wasps harvest decaying wood material. This wood material, once mixed with saliva, produces a paper-like substance used to construct intricate and often very large nests. Wasps build nests in voids found in homes (attics, walls, trees, bird houses), fences and sometimes in underground vacated animal dens.

Unlike bees and social wasps, solitary wasps do not participate in a social system. Solitary wasps excavate underground tunnels or build mud nests.

Wasps propagate in spring and early summer. As the worker wasps’ life cycle comes to a close in late summer, their hunt for food is their only purpose and they become very aggressive. While wasps are veracious hunters of pest insects, which is a valuable service; their venomous stings are painful and sometimes lethal. In early spring, remove nests close to human activity. Keep your home area clear of wasp nests by sealing foundation cracks and keeping garbage covered. Consider creating designated ‘wasp’ spaces luring them far away from BBQ and outdoor recreation spaces with bait or pheromone traps. Or give them their own zone. Forewarn your family and friends to steer clear of wasp zones.

The Tachytes wasp, common 

in our area, is a solitary wasp that makes its home underground. So as you can see, it's not as simple as a Friend or Foe. These complex insects present some risk but also provide benefits to our ecosystem. For more, here's a link https://pubs.usgs.gov/circ/1448/cir1448.pdf Identification of Bees in Southwest Idaho—A Guide for Beginners

Why Raised Garden Beds?

Raised garden beds are a great choice for anyone who has a small space or wants to control the soil quality. Another good reason for raised garden beds, it is great for all ages, health conditions, and mobility types. We all love healthy grown foods, so with raised gardening beds it is easier to manage and control the quality of the soil to get better yields.

Evaluate what your needs are, how much room you have, and how much time you want to commit to your gardening space. 
   Consider the different designs available and see what appeals to you. You will want to know your budget and choose the layout or plan that will work best.  

    Check out this site for many great ideas on types of gardening beds and different designs. 

    Look at your location and decide what plants you want, the amount of sunlight you are going to have, and how long your growing season is for your region. Make sure to add in drip irrigation, which will conserve water; set the drip at the base of your plants. Leave space for walking paths around your beds.

    Think ahead, if you need to cover your garden beds to keep out flying bugs and birds, add design components that will make it easy to net the spaces. This type of design is very useful for fall cold snaps when you need to shelter plants from the cold evenings. You can also use hoops for coverings. The size of your bed should be an arms length to reach far enough to get to your produce; 4 feet is a good width for your beds. If you have rodents that burrow, you may need to put down a wire mesh to block any digging into the bottom of garden boxes.

    Soil preparation is key in a raised bed, so adding in compost and organic material is necessary. The beds can be filled cheaply with rocks, gravel for drainage, grass clippings, fall leaves, twigs, branches, logs, even cardboard boxes, or paper sacks.
    Don’t forget to get your mulch on top to retain the moisture. Keep in mind you do not want to put any items in the bed that have insect contamination or chemicals.  
    Get creative in your planning and designing, use what you have, so many different components can be used for raised beds. REPURPOSE, RECYCLE, REUSE!!

Powdery Mildew

Figure 1: PM on Tomato

Powdery mildew is a fungal disease that affects a wide variety of plants. The affected plants have a dusted-with-flour appearance with white to gray powdery spots on the surface of leaves and fruits (Fig 1). It causes cosmetic damage, and defoliation and decreases the quantity and quality of fruit (Fig. 2).

Disease and Development
There are many different species of (Powdery Mildew) fungi. Most species only attack specific plants in the same or closely related plant families. For example, powdery mildew on roses does not spread to grapes.

Powdery Mildew fungi overwinter in buds, twigs, bark, and plant debris. Their spores are carried by wind to new hosts. Low relative humidity during the day favors spore dispersal.

Fig 2: PM on grapes

The optimum conditions for spores to germinate are temperatures between 68 to 77°F and high relative humidity (> 70%). Powdery Mildew spores can germinate in the absence of water and can infect in arid conditions (40% humidity). Water on plant surfaces can kill or inhibit germination. Spores and fungal growth are sensitive to extreme heat (above 90°F) and direct sunlight. Shady conditions are favorable for PM development.

Management
The disease triangle is a useful tool to understand and manage diseases like Powdery Mildew (Fig. 3). The severity of Powdery Mildew infections is a function of the presence of the pathogen, the host susceptibility, and the environment. Powdery Mildew can be managed by good cultural practices.   

Fig 3: The Disease Triangle

The best control is to plant only resistant species or cultivars. Avoid excess fertilizer since plants with abundant succulent tissues are more susceptible to infection. The fungi can be eliminated by removing and burning all infected plant tissues and debris. Tools must be disinfected after use.

Another good control method is making environmental conditions less favorable for the disease. Avoid dense canopies by proper plant spacing and pruning to provide good air circulation, reduce humidity and increase sunlight penetration. Plants should not be planted in poorly drained soils or shady damp areas.

Overhead watering of the leaves during the day and when humidity is low can reduce infection. Water washes spores off the plant and inhibits its germination. This control method is not recommended for vegetables since it may contribute to other pest problems.

Powdery Mildew seldom needs chemical control in residential plantings, but it may be warranted in commercial plantings of susceptible crops like grapes and cucurbits. Chemicals are most effective when combined with cultural control. They should be applied before the disease symptoms appear. Further spread may be stopped or slowed with chemical treatment. Materials like horticultural oil or neem oils have a low environmental impact. Apply every 7 to 14 days throughout the season. Do not apply to drought-stress plants when the air temperature is above 85° nor within 2 weeks of a sulfur spray. Wettable sulfur is very effective in preventing infection. Like oil application, it should not be applied when the air temperature is over 90° nor within 2 weeks of an oil application.