Category Archives: erosion control

When Rainfall Causes Problems

If you were waiting for some rain before planting to control erosion wait no more. That last storm brought plenty of the wet stuff and the next round is hopefully not far off. You?ve gotten a reminder of those areas that need stabilization during the rainy season.

Fall is the perfect time to start planning and planting. The nights are cooler, the days shorter and the soil still warm. Everything that a new plant needs to get a good start.

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Steep hillside at author’s house covered with erosion control plantings

Using the right plants on hillsides can help slow, spread runoff and prevent soil erosion. Often they need to adapt to shallow, poor soil and cope with less than ideal conditions all while putting down dense, strong roots. Mulch also protects soil from direct rain impact and slows runoff across bare soils. This is important while new plants are growing in. Covering the steepest slopes with jute netting through which plants may be installed is an added precaution.

What plants are good for controlling erosion in our area? When choosing plants to cover a bank for erosion control, assess the conditions of the area you want to plant. Is it in the sun or shade? Is it a naturally moist area or dry? Do you intend to water it or go with our natural cycle of wet in the winter and dry in the summer? Matching the plant to the site conditions will ensure success. California natives are well suited to this job.

If the area you need to stabilize is large and mostly shade, consider ribes viburnifolium or Evergreen Currant. Like mahonia repens or Creeping Mahonia it needs no irrigation when established. Another native, the Common or Creeping Snowberry can also hold the soil on steep banks, spreading by underground stems that stabilize the soil.

A bank in the sun would contain a different plant palette. Common native shrubs for sun include ceanothus groundcover types such as ?Centennial?, ?Anchor Bay? and maritimus that are not attractive to deer like the larger leaved varieties. Manzanita are also excellent at controlling erosion.

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Western mock orange aka philadelphus lewisii

Some other good California native shrubs for erosion control are Western redbud, mountain mahogany, Western mock orange, lemonade berry, toyon, bush poppy, matilija poppy. spicebush, pink flowering currant and Western elderberry.

Smaller natives that put down deep roots are yarrow, coast aster, California fuchsia, wild grape, mimulus, buckwheat, wild rose, sage, deer and needle grass, Pacific Coast iris, penstemon, artemisia and salvia.

Remember when setting plants on a steep slope to arrange them in staggered

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California fuchsia

rows. Make an individual terrace for each plant and create a basin or low spot behind each one ( not around the stem ) to catch water. Set the crowns of the plants high so they won’t become saturated and rot after watering and make sure mulch does not build up around the stem.

These suggestions are just a few of the plants that control erosion. Every area is different and every situation unique.

Dry River Beds – Beautiful & Beneficial

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Dry river bed down a steep slope

With so many people replacing their thirsty lawns with low water-use plants, I?m getting lots of requests for ideas about what to do with all that empty space. The sky?s the limit when you have a blank slate. Let me get you started.

If your old lawn was in the front you might consider putting in a sitting area for a couple of chairs and a bistro table. Use simple crushed gravel or more formal flagstone underfoot and surround the space with a low seat wall to add a bit of privacy.

Adding a dry river bed is another good solution. A dry river bed can slow runoff, spread it out and sink it back into the soil. Connected to a downspout they keep even more rainfall on your own property. If we get the El Nino storms that are predicted this will be a welcome addition to your landscape.

A dry river bed is a rock-lined swale that uses rounded river rock in addition to vegetation to allow

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Dry river bed with grasses and deer resistant oleander

runoff to soak into the ground. Make sure there is a 2% slope from beginning to end to ensure that water is conveyed away from your house to the desired location. Non-woven geotextile fabric is often used underneath the rock.

You can create a depression or rain garden at the end of your dry river bed and plant it with plants that tolerate wet feet in the winter. Both a dry river bed and a rain garden allow water to sink back into the ground. The plants remove pollutants from the runoff from roofs or other impervious surfaces.

A rain garden might be a simple, shallow depression filled with plants that can flourish in both moist and dry conditions. The size and depth will depend on your how much water you need to capture in a winter runoff

Sometimes a dry river bed will receive so much runoff that a dry well or dispersal pit is installed at the end. If you have a high water table or clay soil the water may not always soak in fast enough and an overflow device like this is needed. The goal is to keep water on your own property and not in the street or the neighbors? yard.

There are good looking dry river beds as we?ll as bad looking ones. A quick Google image search will show you what I mean. Your goal is to create something that looks like it belongs right where it is. The plants, the accent rocks, the cobble, the location – all need to work together.

If your property has a natural slope follow the natural terrain if possible. You can install a dry river bed on flat land also by creating a channel for the river bed to follow. Keep in mind that even a dry river bed is more interesting if it is not all visible at once. Soft, flowing curves and bends create a natural look.

Start with the rocks and cobble. Rounded river cobble looks most natural for the creek bed. In nature, water flowing down a river would round off sharp rock edges to produce cobble of different sizes. A river never has just one size of rocks and yours shouldn?t either.

Accent rocks can be any type that you like as long as you get a variety of rock sizes and shapes. Use the larger stones to direct and channel water. Placing rocks on the outside of a curve creates a more natural look.

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Pheasant Tail grass along cobble path

As in all gardens there is always a bit of maintenance to keep things looking and working great. Weeding in the first couple of months while plants become established is important. Replenish mulch as needed until the plants grow in.

Periodically remove leaves that have landed in your river bed and reposition rocks moved by runoff to keep your dry creek bed working for you when you need it. Also don?t start your dry creek bed too close to the foundation of your home if that area is flat. You can direct the water through a drain pipe connected to a downspout to a lower starting spot in your garden.

So whether you are adding a dry river bed to add interest to your lawn-free landscape or to double as catchment for winter storm runoff, make yours look like it?s always been there.

Ormanental Grasses Take Center Stage

phormiumThroughout the year I am asked for design help and plant suggestions but it?s at this time of year that I especially hear the request, ?I?d love to add more grasses to my garden?. There?s no doubt that the movement and sound of grasses in the landscape adds another dimension to our experience. Many grasses and grass-like plants use less water than other plants, too. This is the time of year that grasses say ?Fall is here?.

There’s an ornamental grass for every type of garden. Whether you are striving to create the perfect perennial border or have a hot dry slope, grasses can work in harmony wherever you place them. There are some that are made for the shade, some that are perfect additions to a small water feature and many that are invaluable in container gardening.

Most grasses require little care, minimal fertilizer, only occasional grooming and just enough water to meet their needs. Diseases and insect pests are rare. They have succeeded because of their adaptability and have evolved to suit almost every environment and climate on earth.

Grasses are distinguished from other plant families by their growth habit. They grow upward from the base of a leaf Orange_libertiaor shoot and can regrow from the crown when cut back. True grasses generally have extensive root systems which help control erosion. There are other grasslike plants that resemble grasses in their growth habits and are often some of the best companions for interplanting with grasses. These include New Zealand flax, carex family sedges, chondropetalum-a restio, kangaroo paw, lomandra, montbretia, liriope and their cousins ophiopogon.

So let’s say you are putting in a new patio and want a few low grasses as accents between some of the pavers. A variety like Northern Lights Tufted Hair Grass, with it’s creamy white foliage that turns pink in cold weather, would look great here. You could also use Ogon sweet flag for dense clumps the color of buttery in a shady spot, black mondo grass or blue fescue grass for even more color.

If you are trying to create a focal point or destination in your garden and think the texture of a grass with light and movement would be perfect, look to taller varieties to achieve this. Miscanthus purpurascens or Flame Grass grows 4 to 8 feet tall in the sun. Their magenta leaves turn to milky white in winter. Maiden grass sports narrow upright leaves 5 to 8 feet tall and creamy flowers. Their seed heads float and bounce in the the breeze. Planting them just above the horizon allow you to enjoy their swaying and dipping backlit at sunset.

Japanese_Blood_grassBesides texture, grasses provide color for your garden, too. Who hasn’t admired the burgundy foliage of red fountain grass? it’s one of our most popular grasses with it’s fox-tail like coppery flower heads. Another favorite of mine for color is Japanese blood grass, You’ll love this grass when you place it so the sun can shine through the brilliant red blades. This grass spreads slowly by underground runners and grows in sun or partial shade forming an upright clump 1 to 2 feet tall. Pink Muhly grass will stop traffic when in bloom.

Are sections of your garden hot and dry? Grasses are survivors and are good choices for sunny spots that get little irrigation. Good drainage is a must for these plants so OLYMPUS DIGITAL CAMERAamend the soil with plenty of organic matter before planting. Combine drought tolerant grasses with companion plants and a few accent rocks to complete your dry theme. Good combinations for these areas are Pheasant Tail Grass with the sky blue flowers of Russian sage. This grass is extremely drought tolerant once established. Giant Feather grass looks great with the purple flowers of penstemon ‘Midnight’. If you like blue foliage, try ‘Elijah Blue’ fescue grass with Amazing Red flax for a show stopping combination.

For a touch of whimsy, you can’t beat fiber optic grass. This grass-like sedge from Europe and North Africa looks like a bad hairpiece. You can grow it at the edge of a shallow pond or display it inside in a pot on a pedestal to show off it’s flowering habit. Seeing is believing with this one.

These are just a few of the places where grasses can enhance and add beauty to your garden. Fall is the perfect time to plant a new one.