Root Riot: Taking the Mystery Out of Gardening Terminology Root Riot: Taking the Mystery Out of Gardening Terminology
I was so excited when she asked me for my help in planning a perennial garden. I immediately pulled out all of my books and magazines, ready to assist her in whatever way I could. I started blabbering about bulbs, tubers, and root systems and what could be layered on top of what. I was so focused on giving her information on different types of plants that I missed giving her the basics on root terminology - what it all meant. Thankfully, she forgave my oversight, but it did help me realize just how important this information is.
Root systems are the lifelines of most plants. It is how they get their food and water from the soil. It is what they store reserve nutrients in to carry them through the winter months. Root systems also anchor the plants into the ground, preventing them from falling over, like the prop roots in corn, or from losing the soil around the plant. There are also plant categories that refer to the way in which a plant grows. Here is a list of terms that are helpful to know:
- Fibrous Roots: This term refers to a type of root system that consists of hundreds of fine root branches that extend into the ground in every direction. Most annual plants and many perennials have this type of root system. The older the plant, the more extensive the root system. For many perennials, especially perennial weeds, if even a small portion of the root system is left in the ground, a new plant can develop from it.
- Taproots: This type of root is long and tapered, extending from the base of the stem, vertically into the soil. Oftentimes, there are fine lateral roots used for collecting nutrients, but the main source of nutrients and moisture are obtained by the tap itself. It is also where the excess nutrients are stored. The most widely recognized taproot is the carrot, but other examples are found in dandelions, mimosa trees, and parsnips. Again, the older the plant, the longer the tap. A single piece of taproot can generate a full sized plant. For any homeowner who has battled dandelions in their yard, you know what I mean.
- Aerial Roots: These root systems have two main functions. They help hold the plant in place, usually suspended above the ground, and they pull moisture from the surrounding air. Many types of vines have aerial support roots, like ivy and Virginia Creeper. Other plants, like wild orchids, never touch the ground and depend on their aerial roots to glean moisture from the air.
- Runners: Runners are not considered roots in the classic sense but are a part of the root system, in that they provide a way for plants to reproduce themselves below the soil surface. For example, many blackberry and raspberry plants use runners under the ground to extend their growing area. When dug up, they have secondary rootlets to provide anchoring, but the runner’s primary goal it to extend beyond the parent plant, break through the surface of the soil, and produce a new plant shoot.
- Rhizomes: Rhizomes are really portions of thickened stem that grow either partial or completely below the surface of the soil. Roots develop along the underside of the rhizome to collect nutrients and moisture, as well as to provide stability. Growth buds along the top of the rhizome provide the location for the leaves and blooms to break through the soil. Most irises grow from rhizomes. Planting depth for this category range from 1-3 inches below the soil surface.
- Bulbs: Bulbs are similar to rhizomes in that they are a type of modified stem, which is surrounded by a type of fleshy leaf, often called scales. Nutrients are stored in the scales over winter months, providing the energy and food for the small embryonic plant, found in the center of the bulb. Tulips and lilies of various kinds grow from bulbs and require a long period of cold, usually generated during the winter months. In the spring, leaves sprout from the bulb top and develop into the parent plant. When the plant matures, small bulblets (mini underground bulbs) form on the outer layer of the main bulb, and eventually break off to form their own bulb and embryonic plant. In some lilies, small bulbils (mini above ground bulbs) form where the leaves attach to the stem. Each bulbil will eventually develop into a bulb. Most bulbs are perennial, coming back year after year, depending on the individual plant's hardiness zone. Planting depths for bulbs range from 3-8 inches, depending on the variety of bulb.
- Tubers: Tubers are also a type of perennial bulb. They are a modified thickened stem with growth buds found along the top of the tuber. The roots of the tuber appear along the underside of the "bulb," establishing anchorage for the developing plant. The tuber is the reproductive and food storage unit for the plant. Potatoes, begonias, and dahlias are all types of tubers. Most tubers are hardy only in the warmer zones, typically 8-10, so read the planting instructions on the package before treating them like perennials. Plant depths depend upon the variety of tuber, but generally range between 3-6 inches.
- Corms: Corms are very similar to bulbs, but are shorter and rounder. The bottom of the corm is concave and generally shows evidence of the roots from the previous year's growth. The corm tops are usually flat, with evidence of growth buds. Corms can be confusing to plant because it can be hard to distinguish the top from the bottom. Gladiolas, crocus, and freesia are all examples of corms. Corms are often very prolific in replication, with one corm developing into 10 corms in just one growing season. Planting depths range from 1-6 inches, depending on the variety.
- Bare root: Generally reserved for woody plants like trees and shrubs, bare root plants are shipped in a dormant stage. When the first cold snap occurs and the leaves die and fall off, many deciduous plants become dormant, meaning that they stop growing and expending energy, in effect appearing lifeless. When plants reach this point, it is possible to dig them up, wash their roots, and package them for sale. Many mail-order nurseries collect smaller trees and shrubs during this time and package them for Spring shipments. Dormancy is a good thing when planting or moving a deciduous plant because it prevents transplant shock. Bare root plants should be soaked in tepid water for at least 24 hours and then planted in their permanent location. When the warmer weather comes, the dormant plant will come alive with new growth.
- Rooted Stock: Many hard and soft wood plants can be reproduced through rooted cuttings. This occurs when a hard or soft wood section of the parent plant is cut at the appropriate time and treated with a rooting hormone. The hormone encourages the cutting to begin putting forth tiny roots. The cuttings are typically inserted into a light weight growth medium and allowed to establish a thick root system. The cutting is then repotted and sold under the heading of rooted stock. One of the great things about rooted stock purchases is that you are guaranteed to have an exact duplicate of the parent plant. Some plants to not grow true from seeds, so cuttings are the best way to reproduce them.
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