Sweet bay is a medium-sized tree, whose aromatic leaves are used as a culinary herb (bay leaf), earning it the distinction of herb of the year 2009 by the International Herb Association. The plant Laurus nobilis (family Lauraceae) is widely cultivated in many regions of the world where it is used primarily as a culinary herb now but in its native Mediterranean it was also used medicinally and culturally. It had the reputation of protecting against natural disasters, especially lightening strikes, and was used in the laurel wreaths worn by ancient poets, athletes, soldiers and Roman Emperors to symbolize victory or accomplishment. Other common names for this species include bay, bay laurel, grecian laurel, laurel and true laurel. Other trees commonly called bay include California laurel (Umbellularia californica) and bay rum tree (Pimenta racemosa), whose leaves and twigs are distilled to produce oil of bay, which is used in perfumery and in the preparation of bay rum (an aftershave or hair tonic, not a beverage). The related L. canariensis, native to the Canary Islands and Madeira, is less hardy than sweet bay and has longer, broader, less aromatic leaves. 
Bay is an evergreen plant that can be grown as a single-trunked tree or a multi-trunked shrub. It also adapts well to pruning and shaping, so can be used for topiary or grown as a standard. Because it is relatively slow-growing, it does well in containers. The glossy, dark green, leathery leaves are 3-4 inches long, lanceolate, with a strong midrib and wavy, finely serrated edges. The smooth bark is olive green to gray in color. The plants are dioecious, with star-shaped male and female flowers on separate plants. Inconspicuous but fragrant, pale yellow-green flowers in spring are followed by small, purplish-black, egg-shaped berries, each with a single seed, on established female trees. Trees are self-infertile, so a male tree is needed to set seed. Bees pollinate the flowers. 
L. nobilis is widely grown as an ornamental plant in mild climates (zones 7-10), but can be grown as a long-lived houseplant or outdoor container plant in cold climates. Although it prefers well-drained soil and regular moisture, it is fairly tolerant of most conditions but can never be allowed to dry out completely. In its native areas it grows amid damp rocky ravines, thickets and old walls. Indoor plants can be moved outdoors in the spring and back inside in the fall when temperatures are consistently above freezing. If kept in a cool room (35-60˚F), the tree will stay dormant and does not need much light and very little water (just enough to keep the soil barely moist). In a warmer room provide regular watering like any houseplant and as much sun as possible. In the Midwest, container-grown bay trees thrive in full sun (after being acclimated from the darker indoors) but in warmer climates they may benefit from light shade. 
Once established, prune the bay tree annually to keep it growing vigorously – also providing supply of bay leaves for cooking. Pruning is best done when the tree is not actively growing to maximize growth but to maximize flavor, harvest leaves in the mid summer. Container-grown plants should be repotted to maintain a balance between the size of the roots and that of the top. Prune the roots by cutting off all the roots where they had touched the surface of the old pot whenever the plant is repotted. The roots should be pruned at least every two years (even if the plant is to stay in the same pot) and add fresh compost-soil mix to replace that removed with the roots. Bay is difficult to propagate but this can be done from fresh seed (germination is rather erratic and the seed bed needs to be kept warm), half-ripe cuttings taken in summer (which may take several months), or by air-layering. This plant has few pests but scales can be a problem, particularly indoors. The bump-like insects can occur on both the leaves and woody parts. 
The mature leaves can be used fresh but when dried, the oils are more concentrated. This herb is typically used in stews, roasts, casseroles, and soups with a relatively long cooking time, and also for pickling, in marinades and in teas. Dried leaves can also be used in potpourri, for wreaths and other craft projects, or to repel pests such as silverfish or stored product insects. The essential oil is used in massage oil.
– Susan Mahr, University of Wisconsin – Madison
Exploring the Roots and Stems of Bay Laurel Plant: Anatomy and Function
Bay laurel (Laurus nobilis), also known as sweet bay or Mediterranean bay, is a versatile evergreen shrub or small tree valued for its ornamental appeal and use as a culinary herb. The roots and stems of the bay laurel plant provide structural support and transport important water, nutrients and sugars to sustain growth and development. In this article, we will take a closer look at the anatomy and function of the roots and stems that allow the bay laurel to thrive.
Bay Laurel Plant Overview
Bay laurel is native to the Mediterranean region and belongs to the family Lauraceae, which includes the avocado, cinnamon and sassafras trees. It can grow up to 10-20 feet tall in ideal conditions. The leaves are dark green, aromatic and often used dried or fresh in cooking. Small yellowish flowers blossom in spring and develop into oval black berry-like fruits. Bay laurel is hardy in USDA planting zones 8-10 and can be grown in containers and overwintered indoors in cooler climates. It does best in full sun and well-draining soil.
The Root System
Roots serve the vital functions of providing structural support, absorbing water and nutrients and storing carbohydrates or sugars. The bay laurel root system is characterized as follows:
-
Taproot – As a young seedling the bay laurel plant develops a primary taproot that anchors the plant and drives initial growth downward.
-
Fibrous roots – Over time, the taproot is succeeded by a mass of fibrous feeder roots that form a network spreading horizontally and vertically close to the soil surface. This increases surface area for effective absorption.
-
Shallow depth – Most roots grow in the top 12-18 inches of soil, rarely extending deeper unless growing conditions necessitate it.
-
Root hairs – Microscopic projections called root hairs dramatically increase surface area for absorption of water and dissolved nutrients.
-
New growth – The portion of the root system closest to the stem tip generally shows the most new growth and root hair development.
-
Root tips – Actively growing root tips have a protective root cap that shields the inner growing region as it navigates the soil.
-
Root-soil interface – Root excretions support beneficial fungal associations at this dynamic intersection to aid growth.
Water and Nutrient Uptake
The extensive surface area of the fibrous roots and their root hairs allows for the rapid absorption of water to replace transpiration losses from the leaves. Root cells use osmosis to draw water into the xylem tissues for conduction up to the leaves. The highly branched structure provides a large contact zone between roots and the surrounding soil to acquire nutrients like nitrogen, phosphorus and potassium. Mycorrhizal fungi that colonize the roots aid in nutrient capture.
Food Storage
In addition to water and nutrients, roots also take up sugars produced during photosynthesis and store them as energy reserves. The taproot and larger lateral roots have specialized storage cells for stockpiling carbohydrates that can be tapped into when energy demands exceed photosynthetic supply. This reserved food source helps fuel new growth and supports the plant during dormancy.
Anchorage and Support
The root system stabilizes and anchors the bay laurel firmly in place to withstand environmental forces like wind and rain. Wide spreading surface roots provide the best bracing power. Deep roots help stabilize taller, mature trees. Strong woody roots keep container specimens upright.
Vegetative Reproduction
Bay laurel can propagate vegetatively from rhizomes, shoots or suckers arising adventitiously from the lateral roots. These give rise to genetically identical clones of the parent plant. Detached roots can also generate new shoots and plants.
The Stem System
The aboveground woody stems or trunks of the bay laurel provide several important functions:
-
Structural support – woody tissue strengthens stems to support leaves, branches and fruits
-
Transport – specialized xylem and phloem tissues conduct water, nutrients and sugars
-
Energy storage – parenchyma cells store carbohydrate reserves
-
Reproduction – stems house buds containing shoots that give rise to new branches and grow the plant
Anatomy
The stem’s complex vascular system comprises:
-
Epidermis – outer protective cell layer
-
Cortex – storage cells beneath epidermis
-
Vascular bundles – regularly spaced clusters containing:
-
Xylem – tubular dead cells that lift water/nutrients from roots
-
Phloem – living cells that transport sugars from leaves down to roots
-
Cambium – active cell layer that adds xylem and phloem cells
-
-
Pith – spongy core cells transport nutrients laterally between vascular bundles
Woody Growth
As the stem ages and expands in diameter year after year, new xylem is added by the vascular cambium. This creates characteristic growth rings visible when the trunk is cut. The buildup of woody xylem tissue provides strength and stability for the increasing size of the tree.
Leaves and Branches
Leaves arise from buds located at nodes along twigs and branches extending off of main stems. Branches grow longer each season from shoot tips and add foliage and flowers. The vascular system integrates branches seamlessly with the main stem to deliver water, minerals and food.
Energy Storage
Parenchyma storage cells in the cortex and pith allow stems to stockpile carbohydrate reserves from photosynthesis. This energy can be used to fuel metabolism, new growth or dormant period survival. The stem’s extensive network of vascular tissues facilitates mobilization and distribution of these reserves.
Compartmentalization
The multi-layered construction of woody stems allows for structural reinforcement and healing processes. Decay from wounds and injuries is confined to localized compartments via closed walls of impermeable cells. Nearby healthy tissues are preserved to sustain the plant.
Clonal Reproduction
New bay laurel plants can sprout vegetatively from stems in a form of asexual, clonal reproduction. Horizontal stems can take root when they contact soil. Vertical shoots can arise from bud nodes and be detached to generate genetically identical new plants.
Environmental Cues
The stems sense and respond to various signals like light, gravity, moisture, and touch through growth patterns and hormone distribution. Shoots grow towards light sources while roots grow away from light towards moisture and gravity. Stems flex and reinforce to counteract physical disturbances.
Featured Articles by Season
Ask Your Gardening Question
If you’re unable to find the information you need, please submit your gardening question here:
Plant Anatomy and Structure
FAQ
What is the root system of a bay tree?
Do bay laurel trees have invasive roots?