Wednesday, May 27, 2009

What makes a good dry streambed?

Dry riverbeds can be a very ornamental addition to a low water use garden, or they can be horribly ugly! Here are a few things to think about when planning a dry riverbed:

This first image is an actual dry stream. Instinctively, we know when we are looking at something designed by nature, but what are we actually seeing here? Paying attention to nature can make all the difference between a dry streambed that looks awful and one that increases the curb appeal of your home.

1) Streams happen at low spots because that is how water flows. Because of this, your streambed needs to be carved out in a gentle "u" shape. This sounds obvious but is the most overlooked element of a well designed dry riverbed.

2) Water sculpts real streams. In times when the stream is high, it carves away at the streambank, leaving behind larger boulders that are carved into the banks, not placed next to them!

3) As the water flow lessens through the spring, the heavier cobbles fall out of the flow, getting deposited towards the outside of the streambed while the middle of the stream is still flowing. As this continues, the middle of the stream becomes a pattern of smaller cobbles and gravel. A common mistake is only using one size of smaller material for the center of the stream.

Here are a few examples, some better than others:

This is a pretty high quality artificial streambed. The side boulders are fairly artistically arranged and they have used varying sizes of cobbles in the stream. It has the "u" shape and this allows for the small bridge.

This one is what the industry refers to as a necklace because the boulders are strung along the edges without any breaks. Natural streams do not do this. Also, the cobble in the center is all large an the same size.

This stream is not bad but a few small changes would have made it significantly more natural: a deeper dug out "u" shape and more rounded boulders. Boulders along a stream have been eroded by the water so they have sinuous soft shapes, not hard edges.

This dry river does a few odd things. It is not dug out at all so it looks like the gravel is scattered on the ground like a pathway. The boulders are quite angular and they have created little dams using ledgestones, which don't look at all like something a stream would naturally do since ledgestones are very angular and not at all weathered looking. At least it isn't a necklace, and the accompanying plantings are quite nice.

Fake shakes

I typically steer clients away from products that are man-made reproductions because they mostly don't come close to measuring up to the original. I find this to be true for almost all porcelain tiles attempting to be stone (with the exception of Porcelanosa). And while artificial stone veneers are often a cost effective option, I think they don't hold a candle to natural stone, especially now that there are so many thin cut veneer stones available (Thompson's Building Materials has my favorite selection for natural stone veneers).

So when I find a man-made product that I can't tell is fake, I think it is worth noting. The fiber cement shingles by Nichiha are one of these products. Natural cedar shake is expensive and requires a lot of upkeep. Nichiha's option gives the same look without repainting or restaining. They designed them to have a lot of variation so they look hand-stained, and the colors are fantastic. Dixiline is supposed to start carrying their brand locally.

Friday, May 22, 2009

How to un-slip slippery tile

Since outdoor tile and stone can become very slippery when it rains, I like to use a micro-etcher on any honed natural stone tiles, porcelain tile, or other potentially slippery paving outside. My favorite is a local company called Sliptech. Here is their website:

Their product creates tiny pockets in the surface of the tile. We test it on each material before applying it on the job, but so far it has not drastically changed the finish or color of anything I have tested it on. I would probably be more hesitant to use it on a polished stone, since it may cut down on the shine, but I wouldn't typically use a polished stone outside anyhow.

Not having to worry about the slip factor opens up a whole new world of products for use outdoors. I especially recommend the treatment when doing a waterjet mosaic in the front entry, since these are often honed.

Wednesday, May 20, 2009

No longer astroturf but.....

In the search to save water a lot of people have been deciding to put in artificial turf. Hundreds of companies have cropped up with newer, better, fake grass. Aesthetically, it has made leaps and bounds recently, but when my clients ask if I recommend using it, my answer typically is "no". So I wanted to take the opportunity to compare the up and down sides of artificial turf.

The upsides:

1) It doesn't need to be watered. At Kate Presents, we consider this a pretty big upside.
2) It doesn't need to be weeded, mowed, fertilized, or aerated. It is easy for people with busy lifetsyles.

The downsides:

1) It isn't grass! It isn't alive so you lose the benefits of real life plants. It doesn't remove carbon dioxide from the atmosphere. It doesn't cool the air. It doesn't squidge nicely under your toes when you walk barefoot.
2) It can get quite warm. Be especially aware of companies that use recycle tires for their filler material. It is black rubber, so it can get hot enough to burn kids and pets feet. Opt for the sand filler instead, if the company you chose offers it.
3) It is a petroleum product. There really isn't any avoiding the central issue that it is essentially a green plastic carpet laid down outside. I'd like to see us use less plastic in the landscape, not more.
4) Most brands are not recyclable. With a few noteworthy exceptions, the backing and blades are inseparable and therefor unrecyclable. ProLawn is one of the few companies that has a product hat can be recycled.
5) It is expensive. Although it is possible to find deals in the $8-9 a square foot range, most companies offer their product at around $12 a square foot installed.

So what else is there? I think the key is that we need to let go of our belief that gardens should be 90% lawn with some trees and shrubs around the edges. It is possible to create beautiful outdoor spaces without a lawn or a fake lawn. Here are a few images that I hope illustrate this:

Friday, May 15, 2009

Pseudo- English gardening

A lot of people love the English Garden style with its colorful perennial borders and boisterous flowers, but a typical English garden is very high maintenance and typically high water use as well. Here are a few drought tolerant and low maintenance plants for an English/California garden:

From top left: Penstemon 'Margarita Bop', Buddleja davidii, Anisodentea hypomandrum, Geranium 'Johnson's Blue', Lavatera 'Red Rum', Gaura lindhamaerii, Artemesia 'Powis Castle'

Tuesday, May 12, 2009

Why so grey?

A lot of my clients ask me if there is a way to tell whether or not a plant is drought tolerant just by looking at it. They want to be able to impulse purchase plants at their local nursery and know that they will work in their low water use gardens. It isn't always possible to tell, but the following can at least be helpful.

Drought tolerant plants, or plants that will work in a xeriscape garden (which comes from the word xeric, which just means dry, not from zero, as many people think), are going to have a few simple characteristics that they evolved to help them live in dry climates. If you look for the characteristics, they can be the give-away for what the plant might want.

1) Xeriscape plants often have a grey-green color to their leaves, not a green-green. This is because they are from places where light is abundant but water is scarce. They want save their water but can afford to loose a few chlorophyll cells. Plants that live in places like rainforests have the opposite problem. They get plenty of water but are probably shaded by a tree canopy, so they want all the chlorophyll they can get in their leaves so that they can absorb what little light comes their way. So rule #1 is: Grey-green is probably drought tolerant. Green-green is probably not.

2) Dry climate plants may be fuzzy. This layer of fuzz helps them to lose less water from evaporation. Wet climate plants will almost never be fuzzy- they will be waxy instead, like a Philodendron. So rule #2: fuzzy probably indicates drought tolerant and waxy probably indicates water loving.

3) Xeriscape plants tend to have small leaves. This also helps them conserve water because the pores in leaves are where most plants lose water from. Since they probably get all the light they need, having small leaves doesn't stop them from doing plenty of photosynthesizing. Wet climate plants tend to have big leaves so that they can soak up more light (think deep forrests, rainforests, shady glens). So rule #3: xeriscape plants have small leaves and wet climate plants have big leaves.

So, which is which?

The first photo, Philodendron evansii, has big waxy green leaves (and yep, it likes its water) and the second photo, Acacia redolens, has grey-green, small leaves. It is very drought tolerant.

Wednesday, May 6, 2009

Everything is coming up roses

Roses have a reputation for being high maintenance- and in my opinion it is a reputation that is fairly earned. In San Diego, we are spoiled enough to think that our gardens should be attractive all year round, and winter time bare branch roses are just not very attractive. However, there are a few varieties that I use often and think of as "easy" roses.

My favorites by far are the Flower Carpet roses. These low groundcover roses are usually about two feet tall and two to three feet wide. They come in about a dozen colors now, and they are unique in that they can produce new growth from their roots, not just from their canes. That means that pruning can be done with loppers. Here are a few of the Flower Carpet series (just to warn you- these usually go for about $20 for a 5 gallon, so you pay a premium for them):

One of the standard low maintenance roses is Rosa floribunda 'Iceberg'. It is a rose you see often, and for good reason. It is one of the simplest roses to grow and has a classic look.

I also think that the Lady Banks roses are worth a try. These are climbing or sprawling roses, great for hanging over the edge of a tall wall or scrambling up and over a short fence.

And for the last of my easy care roses: a great smelling climbing rose that is really a classic. Cecil Brunner is a soft pink with a precious flower and amazing scent. It can be trained up and over larger arbors because its canes cane be 20 feet long. This one is a must have for a country cottage garden.

In coastal San Diego, keep an eye out for powdery mildew. It is common on roses that are getting wet from irrigation overspray or damp air from our June gloom.

Monday, May 4, 2009

Fabulous fruits

I get a lot of questions about which fruit trees grow well in San Diego, so I thought I would list a few favorites that are proven producers.

The fruit tree that I recommend more often than any other is the apple called 'Anna'. It has delicious crispy green/yellow apples with a delicate sweet taste and a reliably un-mushy texture. Because it was developed for growing in Israel, it can handle the low number of chill hours in coastal and semi-coastal San Diego. It also doesn't take a horticulturist to grow this apple successfully, however, it does need another apple tree nearby to pollinate, so if there are not other apple trees close by, consider planting two. The fruit is wonderful for eating raw or for cooking.

I also don't think any garden is complete without some citrus. I love to have at least a lemon and a lime on hand for cooking. There are two popular lemons in San Diego: Meyer lemons and Eureka lemons. Meyers are a little better suited to our climate but have a different flavor than the supermarket lemons, so you should try them first to make sure it is a flavor you like. I think it makes the best home made lemonade. Eureka lemons are closer to the flavor of supermarket lemons. Bearrs limes grow well here and have a great flavor. Make sure to fertilize your citrus with a high nitrogen citrus/avocado fertilizer. Consider buying dwarfs or semi-dwarfs. A full sized citrus gets to be 20' tall - much too tall to pick easily. A semi-dwarf can get about 9-10' and a dwarf will be 5-6'.

A few others that I'd like to note quickly:

- Satsumas are delicious small tangerines packed with flavor. They are easy to grow and prolific.
- There are a few good peaches and nectarines that grow and produce here. Read the label and try for 250 chill hours if you live near the coast and 500 or fewer chill hours if you live a little further inland. I like 'Babcock' but there are at least a half dozen well suited varieties.
- We can grow a lot of figs here. 'Black Mission' is the most common. Figs are very prolific but they can self seed here, so I don't recommend them if you live on a canyon or open space. They can also attract rodents. Because of these issues, I like to grow figs in a very large pot instead to keep them more in control. If you have never tried it, a ripe fig split in half and drizzled with honey and creme fraiche makes an elegant simple dessert!
- Pomegranates are very easy to grow. Try Punica 'Wonderful'. Pomegranates have large thorns, so don't plant them near patios or walkways.
- Ripe plums are just something you can't get in the store any more. Try growing 'Santa Rosa' for a delicious sweet, explode-in-your-mouth plum.