INTRODUCTION TO PORTABLE GARDENS

Bart Hayes is currently the Horticulture Specialist for the Department of Horticulture and Crop Science at Ohio State University in Columbus, Ohio.  Part of his duties include organizing and managing the Annual Bedding Plant Trials at the University.

Bart is a prolific writer and public speaker.  His articles have appeared in trade publications and he has spoken to groups as varied as industry professionals and garden clubs.

In this article, Bart explains the easy way to build a container of flowers or foliage, from the pot up.  You can learn how to mix colors in a pleasing way, how and when to fertilize, and when to water and how to know when to water.  Using the correct soil-less blend and putting same needs plants together; all of these are recipes for success.

---Anne K Moore August 7, 2009---

PORTABLE GARDENS

Mixed containers have become a huge portion of the garden business.  Their success is due to many factors:  Ease of construction, ease of maintenance, the ability to move from one place to another easily, and the big impact they can have in a landscape.  There are a few basic guidelines for planting your own mixed container combination, but it really is hard to make a bad combination.

Photo: These succulents do well in pots.  They detest clay soil. Plants: Euphorbia tirucalli 'Sticks on Fire', Echivera 'Topsy Turvy', Sedum adolphii, & Cactus species.

The first thing to consider, before choosing plants, is the container itself.  I go on and on about investing in a good container, but for good reason.  The pot makes up half of the combination, so it needs to blend in and not draw attention away from the flowers.  Even better, it should add to the overall beauty; beautiful plants in a great pot is the same idea as a beautiful painting in a great frame. 

Make sure the pot has a drainage hole and is heavy enough to keep a tall plant combination from blowing over in the wind.  Other considerations, which are important but really rely on your own personal preferences, are the color of the pot, its shape and material, and how these factors work with the plants.

The next thing to consider is soil and fertilizer.  I mention the two together because they both rely on each other.  A light, free draining mix, free of sand and gravel, will grow a healthy plant.  Some of the drawbacks of having a mix like this are that the containers will need to be watered more often and they will not hold fertilizer like growing-in-the-ground garden soil. 

A good way to compensate for this fact is to mix a slow release fertilizer into the soil.  That way the plants will have a constant little dose of fertility always available.  I still suggest using a well-balanced liquid fertilizer (the numbers on the label read 15-30-15, or something similar) when you water once every 2 to 4 weeks for that extra kick to make your plants explode with blooms. 

If you do not use a slow release fertilizer, then you should be fertilizing about once a week or every third watering.  I would avoid using regular garden soil, as it can have weeds and diseases that can adversely affect plant growth.  Plus, it is heavy and, if it happens to get too dry, gets as hard as a rock.  Plants can't grow in a rock.

Now we talk plants.  Where to start?  The sky is the limit when it comes to what you can put into a combination planting.  Annuals, perennials, tropical plants, succulents, trees, shrubs, and artistic, non-living things like cut branches or pieces of art all are container worthy.  I hesitate to tell you what to use, only that you should use what you like and think will look good. 

The plants should be in balance with the container, meaning not excessively large or small for the size of the pot.  Remember, the plants will grow after you purchase them, so read the label for a good estimate on the finished size you can expect. 

Now for a little advice:  The pot should be about one-third the finished height with plants making up the other two thirds.  This makes for an appealing and appropriately balanced combination.  Also, take into account the way the plants grow; the plant habit.  Some plants are narrow and very vertical, some are low and trail over the edge of the pot, most are somewhere in between, sort of a half-sphere shape. 

Photo: A great combination for part shade; the palm (Phoenix roebelenii) and Frieda Hempel caladium are the ''taller'' plants, the Non-Stop Bright Red begonia is the ''baller'', and the chenille plant (Acalypha pendula 'Firetail') is the ''faller''.

If you are making a combination, one of each of these plant habits in a container will give each of the plants room to grow, without interfering with each other.  A good way to remember this is ''a thriller, a filler, and a spiller'', or as I prefer to think ''a taller, a baller, and a faller''.  As long as we are discussing design, I will mention that there are some tricks, outside of your own taste, that can be used. 

When picking the color of the plants you want to use, try to match up different colors that either compliment or contrast each other.  Remember back to high school art class and the use of the color wheel:  Colors across from each other contrast; colors next to each other complement.  And don't forget that green is a color, too.  Use plants with different leaf textures and shape to provide even further interest.

Once you have planted your combination, the maintenance should be relatively easy.  Mixed containers require more maintenance than a planted flowerbed, but they are much smaller, so the time investment is less.  The key to taking good care of your combination has three important parts:  Water, water, water. 

Watering is the most challenging aspect of plant care, even for professionals.  You need to find the ''Goldilocks level'', not too much and not too little.  A trick that I use at work and at home is to lift the pot.  If it feels heavy for its size, then it probably does not need watered, if it is light, then a drink would be a good idea. 

If your pot is too big or heavy to do this, put your finger about 3 inches into the soil, about 3 inches from the edge of the pot.  If it is cool and moist, you have enough water.  Plants will also ''tell'' you when they are dry.  Some plants have leaves that will lighten in color and become whiter, like Boston ferns and Begonias.  Most will start to wilt. 

An occasional wilt is not a bad thing, but too much too often will result in less flowers and sick looking plants.  When you do water, with or without fertilizer, you want to water thoroughly, but infrequently.  Keeping the soil saturated all of the time is not good.  The roots need air too, not just water. 

Add water until you actually see it coming out of the drainage hole.  Be patient!  This may take awhile; you may even have to water it, stop, and then water again.  I can't say when to water again because so many factors go into how much water is available for the plant.  The size of the pot (a smaller pot needs more water), the kind of plants that you use (a cactus uses less water than a petunia), and where it is located (in full sun or in the shade) determine how much and how often you need to water your combination.  All I can do is tell you that it is OK for the soil to dry out a little; it encourages the plant to grow healthy roots.

A container garden can do many things.  It can brighten up a dark spot where you cannot plant something in the ground.  It can enhance an outdoor living space, make a great gift, or simply allow you to enjoy gardening without having to do more work than you are willing or able to do.  I like to move my containers around when I have company or when I get bored with how my yard looks.  It is an easy fix for hiding bad spots or enhancing good ones.  No matter how you use your mixed containers, I am sure you will enjoy them; all it takes is an artistic eye, a love for plants and to garden smart.

PHOTO: Shade container using mostly foliage colors (a monochromatic complimentary scheme) brightens up a shade corner.  Golden Boston Fern (Nephrolepis exhaltata 'Rita's Gold'), Begonia 'Marmaduke', Lysimachia 'Walkabout Sunset', and Guzmania Hybrid