Pat Welsh Southwest Garden Advice, plus garden ideas for everyone » Pots & Containers

Drought tolerants for patio

Pat — Thu, 22 Apr 2010 08:21:39 +0000

Question from Tracey:
I would like to find out if there are some drought tolerant /native plants that will do well in pots on a patio. The patio is south facing and gets a lot of sun. I’m in the South Pasadena/ Highland Park area of Southern California.

Answer from Pat:
A few native plants can be grown in containers, such as grasses. Mexican feather grass (Nassella tennuissima), for example, native to Texas, New Mexico, and Mexico, is one of the most drought-resistant of ornamental grasses often seen mixed with other plants in containers. But in my opinion if you are looking for the most satisfying theme of drought-resistant plants for patio containers, your answer is succulents, and if you like them, also cacti. Two years ago I emptied out all my patio pots, rearranged them in attractive groups of various sizes and shapes, put broken crockery over all their drainage holes, filled them with ordinary potting soil (since it retains moisture so I would not need to water as often), and filled all these patio pots with drought-resistant succulents. I already had some of the plants growing in other parts of my garden. I purchased others at plant shows, botanical gardens, nurseries, and even at my local farmers’ market. With the help of a friend, I carefully arranged the plants to please my eye, playing the various textures and colors and shapes against each other. Then I continued to do the same thing with other potted arrangements here and there throughout my garden.

Few garden projects have given me as much pleasure as has this one or produced such delightful results. Also, once the weather cooled down in fall I stopped watering these pots altogether and told my gardener not to water them. It is now April and we still have not resumed watering. In return for no care other than picking out the occasional snail, the colors, flowers, and burgeoning growth has given us an ever-changing and totally glorious display. In summer I water once a week, if that. Though I have a gardener who comes to my garden once a week, I could go away for a week or a month at any time of year even if no one were caring for my plants, and I know these tough little performers would still be there when I got back. For ideas, see Debra Lee Baldwin’s new book “Succulent Container Gardens.”

Many of these plants can also be grown in hanging baskets. One of my long-time favorites is donkey tail (Sedum morganianum). These thrive in semi-shade, for example hanging from tree branches, as do orchid cacti (Epiphyllums). If you feed epi’s in accordance with the month-by-month instructions in my book, these flowering cacti will also reward you with a spectacular display of blooms in May of many different colors according to variety. Some have iridescent blooms, others are fragrant at night and attract sphinx moths.

Honeysuckle Dying

Pat — Fri, 09 Apr 2010 08:41:46 +0000

Q: Purchased a ‘mint crisp’ honeysuckle in a 1 gal pot; transplanted to a larger planter (hoping to move so I’m trying not to actually plant it). Was doing just fine and growing but has started to have sections where its starting to die. Leaves started to get limp (checked and moisture level was okay not registering dry or wet) but leaves have shriveled up/turned brown…almost like something is sucking them to death but I don’t see aphids or anything. Any help or suggestions on what is going on would be greatly appreciated.

A: Cape honeysuckle (Tecoma capensis) is a vigorous plant whose common name derives from the Cape of Good Hope, South Africa. These plants do not grow well in containers. They need full sun and good drainage and are very drought resistant once established but look better with occasional deep watering. The problem with growing a vigorous drought-resistant plant in a container is that the roots are so vigorous they tend to go round and round. You transplanted your one gallon size plant into a larger container but did you loosen the roots first? Also did you plant in potting soil? Garden soil is not appropriate for plants growing in containers. All plants growing in containers need good drainage. All need to be lightly fed while growing in a container. All plants growing in containers should be watered enough when watered so that water will flow out the bottom of the pot. Though it is a little difficult to judge from the facts you have given me, it sounds to me as if you are not watering enough. Also, be sure plant has full sun. Water thoroughly at least once a week so the water comes out the bottom of the pot and don’t let the roots stand in water. That will kill the plant.

Heat and Cold-Resistant Container Plants

Pat — Sun, 04 Apr 2010 08:20:52 +0000

Question from Brenda:
What are some good container plants for Oklahoma that will make it through our cold winters and hot summers? Thank you!

Answer from Pat:
The hallmark plants for containers in cold-winter climates are hardy evergreens. Your garden center should have a good selection. Books and magazines, especially those on formal landscape design and roof gardens, will give you many ideas for the style of the container and the color and shape of the evergreen. Be sure to invest in pots and containers, such as half wine barrels, that can withstand freezing temperatures without shattering. Also, remember no plant can survive winter outdoors if its roots freeze solidly. In northern Europe, shrubs and trees in containers are brought indoors in winter or treated as annuals. Sometimes the shrub and the container is wrapped to protect the plant from cold, but this won’t work when the winters are too cold.

Look around at local houses and hotels with container-grown plants. This is the best way to see what grows best in your area. One way to spark up container-grown shrubs in milder winters, where temperatures occasionally reach freezing but not far below, is to plant tulips or other hardy bulbs around the roots of evergreens in fall, but again, if the bulbs freeze it will kill them.

The best solution is to fill containers with seasonal color. The choices these days are far wider and more varied than even twenty years ago. Companies such as Proven Winners™ specialize in such plants and you can keep some of the selections going through winter in the house. When you empty out the plants in fall, decorate the tops of the tubs with ornaments, dried grasses stuck upright in the soil, wooden tree forms, or boughs and large colored globes for Christmas.

Problems Growing Squash in Containers

Pat — Tue, 05 Jul 2011 08:52:15 +0000

Question from Martha:
I have 2 squash plants planted in containers, side by side. They started out beautiful. I got 2 nice squash so far. Lately, the tiny squash have been drying up before they get very big, and also the leaves are turning brown underneath the plant. Help! Thank you.

Answer from Pat:
Yellow and browning leaves and shriveled fruit can often mean lack of nutrients, especially nitrogen, or can mean overwatering. Squash plants are also subject to several diseases, such as blight, bacterial wilt, and mildew. You do not mention white on top of the leaves, but mildew causes whiteness on top and browning beneath and finally browning of whole leaves. (See my video on what to do about mildew. One cure for plant diseases such as mildew is to spray the plant with an organic product called ‘Serenade’ which contains a beneficial fungus which attacks and kills the fungus disease.)

You do not describe the type of browning, whether spots or all over. The various diseases of squash have a variety of symptoms and browning can be in spots and in some cases lead to holes through the leaf. To avoid disease problems altogether, always begin squash from seeds of a good disease-resistant variety, not from a plant you buy in a nursery container because when you purchase a container-grown squash plant it will usually be a cheap variety, not disease resistant variety, and also is most likely to be infected with a disease already when you buy it. I have seen very sorry looking squash plants in nurseries and I always wonder why folks don’t plant squash from seeds when the seeds sprout so quickly and easily.

Now to discuss nutrition: Plants growing in containers are dependent on the gardener to give them the soil mix and food they need for healthy growth. However, I am taking it for granted that you filled your container with a good quality potting soil, not garden soil. Filling containers with garden soil is a recipe for disaster. I also imagine that you have fertilized, according to package directions, with a balanced organic fertilizer appropriate for vegetables. Diluted fish emulsion can work well for vegetables in containers, since it does not burn. Plants that are not fed will go yellow or brown and the fruit will abort and fall off, as you have described.

Squash needs plenty of room and a large container. A half barrel size is about the smallest one can go. Early in the season before the sun is so hot it is possible perhaps to get some fruit, as you did, but once the weather warms up and the roots inside the container wind around the inside of the container where the sun hits, those roots will fry from heat and they literally burn. It is natural that some early leaves might go brown and shrivel up, but in a really healthy plant most of the leaves will be large and stand up high to shade the fruit. Next time plant squash in a large container, or begin by planting one of the miniature varieties especially designed for growing in containers. Even a raised bed is sometimes not big enough for an ordinary squash plant, since one squash plant needs all the space in the bed.

Sometimes people overwater their vegetables. If the soil mix is soggy wet, as can happen in containers, or if it is uneven in moisture this can result in problems. Squash like best to be grown in the ground and to be watered deeply and infrequently instead of shallowly and often. Soil mix in containers dries out quickly and this forces gardeners to water the plants more often than optimum conditions require.
As far as the drying up of little fruits, this too can be a result of root burn. Another possibility is that there were no bumble bees in your garden so they never got pollinated. Try hand-pollinating the flowers as demonstrated in my video on the subject. (Click on “videos” in the right hand column and then click on “See all 24 videos”.)

Organic fertilizers for indoor plants

Pat — Fri, 14 May 2010 08:10:54 +0000

Question from Randy:
I would like to know what is a good indoor plant food? I’m going to start worm composting and am now composting my yard clippings etc. but am unsure about using these things indoors (smelly). I really like your S.Ca. organic gardening book.

Answer from Pat:
When gardeners decide to go organic they naturally want to use organic fertilizers indoors also. Unfortunately, most organic fertilizers add brown color to the drainage water or they are odiferous or both. As you have pointed out earthworm castings and homemade compost are inappropriate for indoor use and regardless of that, though both contain nutrients, neither is considered to be a fertilizer. But there are fertilizer products you can buy or make for yourself that are organic and yet have no odor. One of these is deodorized fish emulsion. Several brands are available, most of them are fully organic, and some bear the OMRI seal of approval.

When you feed houseplants with deodorized fish emulsion, the water that drains out the bottom of the pot may nonetheless have a brown tint. Solve this by taking care when removing excess drainage water from the drainage dish under the pot. The best solution is to fill the dish under the pot to the brim with gravel and place the pot on top. Then periodically use a bulb baster to transfer the excess water from the gravel into a bucket while taking care not to get spots on the carpet or bare floor. Or place the plant and its container inside a cachepot with a layer of gravel or pottery risers inside to hold plant roots safely above drainage water. Use the bulb-baster system to remove drainage water whenever necessary.

Other organic liquid fertilizers for indoor houseplants include products developed for hydroponics. A number of these products have no odor whatsoever and you can purchase them by the gallon or sometimes in smaller quantities. For a homemade organic fertilizer, you might try mixing up ordinary unflavored gelatine with hot water. Once dissolved, dilute the mixture with enough cold water so it’s no longer hot and then pour it on plant roots. Gelatine is almost pure nitrogen. If you think your plants need some phosphorus and potassium too, save and chop up all your banana peels for a week and put them into a quart jar filled with water. Let them ferment for a week or so and then pour the water on the plants. In my garden I have not noticed fermented banana peel water attracting any pests, either animals or insects and I actually throw the peels on the ground too. Until now I haven’t tried using the water on house plants but now I just may do that to see how it works.

Potting Soil or Potting Mix?

Pat — Mon, 05 Apr 2010 08:57:09 +0000

Question from Fred:
We are a bit confused about what to plant our Sweet 100 cherry tomatoes in. I have a 10 gallon container and need to know whether to use potting soil or potting mix and whether the brand is important. Also, if I use potting soil what kind of fertilizer (or tomato food) should we use.

Answer from Pat:
Dear Fred, You perhaps attended my talk where I said to fill raised beds with topsoil not potting soil. This is correct. A raised bed is like a terrace and should be filled with topsoil which should be amended with organic soil amendments and fertilizer prior to planting every time you plant in order to maintain a good humus content. In other words you should treat a raised bed just like garden soil.

A 10 gallon container is different. This is a container, a pot in other words. In this case, plant in good quality potting soil. Potting soil is a man-made mix especially concocted for growing plants in containers. Garden soil as a general rule is not a good thing for filling containers. I hesitate to name brands since they change from time to time, but I can suggest this. Go to a good nursery and purchase a potting soil there. Do NOT purchase a sterilized potting soil. Sterilized potting soil has no active nutrition in it. Very often this product doesn’t even drain well.

After planting your tomatoes, keep them watered more frequently than you would if they were growing in the ground and fertilize them regularly with an organic fertilizer recommended for tomatoes. Liquid fertilizers work well if you can find an organic fertilizer recommended for tomatoes. If you decide on fish emulsion instead, then also spray the foliage with 1 teaspoon of Epsom salts mixed into a quart of water in a small hand-held sprayer. (Laundry-dampening type household sprayer.) Spray all over the leaves once or twice a week apart in the early morning or evening when the plant begins flowering. This will provide magnesium.

Also, make sure flowers are pollinated by wind, or if there is no wind shake the plants lightly in the middle of the day or bang the stakes with a hammer in the middle of the day. Tomato flowers are self-pollinated by wind, banging the stakes with a hammer does a great job of vibrating the flowers just right so the pollen falls of the male stamens and attaches to the female stigma.—Voila!—self-pollinated tomato flower that will not drop off the plant. (Cool temperatures can cause flowers to drop off early in the season. Fix that with tomato blossom spray.)

Success with Potted Bougainvillea

Pat — Fri, 18 Dec 2009 18:57:01 +0000

Q. I have a bougainvilla. It’s potted in a large clay pot on my balcony. It faces the South and I live in Marina del Rey. I watered it once a week… about 1/4 a gallon. I slowed the watering down, sped it up. Moved it to a bigger pot. Nothing I have done seems to improve its health… what do you suggest?

A. I have seen gorgeous bougainvilleas growing in lava-filled pots in Hawaii and mighty few really spectacular ones in California, but I have a photo of one that was growing in an 18-inch patio with a small trellis behind the plant that was stuck down into the pot. The plant was in full sun. The owners told me they watered weekly and every other week fed it with Miracle Grow according to package directions.

Based on this, I suggest growing in a sheltered sunny location and fertilizing regularly. Water once a week by applying enough water so that water drains out the bottom of the pot; this flushes salts away. (1/4 gallon, or 1 qt., is probably not enough to permit this to happen and will result in a build-up of salts.) Fertilize every two weeks in summer with Miracle Grow and since the plant is not doing well and now it’s winter begin now but fertilize only once a month until February, then increase to every 2 weeks. Mix 1 Tablespoon Miracle Grow into 1 gallon of water and water with it. I usually don’t suggest this fertilizer and it is not an organic fertilizer, but it works for bougainvillea in pots. (Sometimes we bend the rules to make

life easier for apartment dwellers.) South-facing should be good unless there is shade cast by heavy railings or by some object. But if your plant is in cold wind this can effect its condition. Potted bougainvilleas prefer a sheltered location in full sun. However, unless the plant is shaded I think your main problem is that you are not watering and fertilizing enough.

One final caveat: make sure your plant is not sitting in a puddle. Bougainvilleas do not like wet feet.

A word about exposure:

If your south-facing porch is under another balcony or under an overhang it will have full sun in winter, full shade in summer, an ideal situation for people, but not for plants like bougainvillea that need full sun. Try to put it in full sun.

Book on Container Gardening

Pat — Mon, 14 Feb 2011 08:47:27 +0000

Question from Julie:
Hi Pat, you were the featured speaker at my Master Gardener graduation in May 2010. On display was a book about container gardening, I would like to know the name of the book and were you the author?

Answer from Pat:
I have not written a book on container gardening, but there are many good ones on the market and the best are chock-ful of easy-to-follow photos. I don’t know which book was displayed at the Master Gardener graduation in Orange County when I was the speaker, but below are a few of container-garden books I’ve heard about. Google these and maybe by looking at the cover photo on the Internet you’ll recognize the book for which you’re searching.
I remember seeing P. Allen Smith’s book recently so that might have been it, but Pamela Crawford’s book is highly recommended too.

Pamela Crawford’s Container Gardening, Volumes 1 and 2.
Fine Gardening: Container Gardening, 250 Design Ideas and Step-by-Step Techniques.
All-New Square Foot Gardening: Grow More in Less Space! by Mel Bartholomew
P. Allen Smith’s Container Gardens

If you look at any of these on Amazon.com’s site you are sure to recognize the book you need. Many are available used and at a discount.

Small Patio Trees

Pat — Mon, 11 Oct 2010 08:26:54 +0000

Question from Margo:
I am having two trees removed and need replacements. One, will be in an elevated triangular planter about 6″ at the widest point. It is directly over a spa. So I need a tree that will not drop leaves and will not have invasive roots. The second was in the ground and I’m thinking about pouring concrete and using a large container for a tree.

Answer from Pat:
Small trees that will grow in a small raised bed or very large tub and are non-drippy are few and far between. Also you do not inform me of where you live, or what climate zone you live in. If you live in Southern California or in the Bay Area (San Francisco and environs) my top suggestion for a small clean patio tree is Rhaphiolepis ‘Magestic Beauty’. This is a trouble-free tree that is subject to virtually no pests or disease. It’s thought to be a cross between Raphiolepis indica and Eriobotrya, but I think it is just a chance seedling of rhaphiolepis, since I had something similar come up in my own garden from a seed. Leaves and flowers are bigger than the other selections and growth habit is taller and more treelike. It grows well anywhere in the largely populated areas of California from San Francisco on down. It is a clean non-drippy tree, good on streets and good in patios. Shear after bloom once a year to keep in shape. Never prune in autumn or winter or there will be no spring flowers!

Fill the raised bed with good quality top soil (Not potting mix!) and add organic fertilizer also measuring the correct amount. But plant the tree in the pot in potting soil (not top soil!) the best quality you can find. Add some organic fertilizer at planting time that is appropriate for trees. Ask your local nursery to order the tree from Monrovia Nurseries or go to a tree farm to get it. They have specimens with various trunk heights. I would be careful to get one with the tallest trunk available. The small ones take a long time to grow taller, if ever. Ask for one with a good pink color but if you think the pink is a bit washed out looking in spring, don’t worry. The color will deepen as the tree ages, which is good. (The deeper pink color of the flowers is preferable.)

The main trick with pruning rhaphiolepis is to follow this rule: “Prune after bloom, never before bloom!” After spring bloom is done, shear off the top of the plant in June every year in the shape of an umbrella, removing all fruits that form after flowers fade and some foliage. Above is a photograph I took of a mature one in bloom that is pruned correctly in June every year. It is about 25 years old. Best in full sun but can survive in half-shade inland.

It is far better to have two of the same thing than two different plants, but if you want another choice I suggest Agnes Galt pink Chinese hibiscus (Hibiscus rosa-sinensis ‘Agnes Galt’) grown on a trunk as a tree, but this may be difficult to find. Another variety that can be grown on a trunk is ‘Angel Wing’. It has big white flowers. These two will survive many years as trees in containers or small raised beds or streetside and also and are clean trees. Prune as my book suggests for hibiscus starting in March. Keep head in umbrella shape. Fertilize through summer. Cover soil mix with dry bagged earthworm castings against giant white flies if they ever attack this tree, but beneficial insects released by the Department of Agriculture are controlling the giant white flies pretty well. Grow in full sun.

Agonis flexuosa ‘After Dark’

Pat — Fri, 30 Jul 2010 08:31:31 +0000

Question from Gail:
Hi Pat, I enjoy your books and website very much–what a wealth of information and inspiration!

My question is about Agonis flexuosa. I’ve planted three of the ‘After Dark’ dark foliaged trees in full sun (Sunset 23) from 3 gallon containers. They are now about 12′ tall.

They’re becoming beautiful small trees, but so far are slim and lanky. Do they require any corrective pruning in their youth? Can I tip back for greater bushiness? So far I’ve done nothing to them but let them grow. Thank you!

Answer from Pat:
I have seen Agonis flexuosa ‘Jervis Bay After Dark’ in nursery cans and display gardens at the county fair and elsewhere. Monrovia Nursery website has a very pretty photo of one growing in a raised bed with wide foliage and looks like a skinny trunk. I have seen other photos that make it look like more of a shrub than a tree. Monrovia says you have to water deeply and often the first year to develop a large root system. After that it’s drought resistant. They also say it’s slow growing to 15 or 25 feet and 10 to 15 feet wide. I have yet to see a full grown one and I have wondered if it is mainly a screen plant or novelty item. But my guess is that only time will tell how well this tree grows in California long term. Meanwhile I would leave the lower branches on as long as possible to encourage the trunk to grow strong. Also don’t stake too tightly. Let it sway in the wind to grow a strong trunk. Also, yes I would pinch back the sides, especially the lower branches take off a foot at least to encourage strength and branching, and do not cut back the top leader or you will dwarf it and make it grow wide instead of tall. Follow the usual guidelines for developing a good branch structure in trees.