Nemesia caerulea ( Nemesia )

This woody-based perennial is also sold as N. foetens and produces lavender, blue, or white flowers with yellow throats from early summer to fall. Growing to a height of 24 inches tall and 12 inches wide, Nemesia prefers moist, yet well-drained soil that is slightly acid. Full sun is best for ample flowering. Also, be sure to water well if weather is dry during the flowering period. Foot and root rot may pose a problem.


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Characteristics

Cultivar: n/a  
Family: Scrophulariaceae  
Size: Height: 0 ft. to 2 ft.
Width: 0 ft. to 1 ft.  
Plant Category: annuals and biennials, perennials,  
Plant Characteristics: low maintenance,  
Foliage Characteristics: small leaves,  
Flower Characteristics:  
Flower Color: blues, pinks, purples, whites,  
Tolerances:  


Requirements


Bloomtime Range: Early Summer to Mid Fall  
USDA Hardiness Zone: 9 to 10  
AHS Heat Zone: Not defined for this plant  
Light Range: Sun to Full Sun  
pH Range: 6 to 7  
Soil Range: Sandy Loam to Some Clay  
Water Range: Moist to Moist  





Plant Care

Fertilizing

How-to : Fertilization for Annuals and Perennials

Annuals and perennials may be fertilized using: 1.water-soluble, quick release fertilizers; 2. temperature controlled slow-release fertilizers; or 3. organic fertilizers such as fish emulsion. Water soluble fertilizers are generally used every two weeks during the growing season or per label instructions. Controlled, slow-release fertilizers are worked into the soil ususally only once during the growing season or per label directions. For organic fertilizers such as fish emulsion, follow label directions as they may vary per product.

Light

Conditions : Full Sun

Full Sun is defined as exposure to more than 6 hours of continuous, direct sun per day.

Watering

Conditions : Moist and Well Drained

Moist and well drained means exactly what it sounds like. Soil is moist without being soggy because the texture of the soil allows excess moisture to drain away. Most plants like about 1 inch of water per week. Amending your soil with compost will help improve texture and water holding or draining capacity. A 3 inch layer of mulch will help to maintain soil moisture and studies have shown that mulched plants grow faster than non-mulched plants.

Planting

How-to : Preparing Garden Beds

Use a soil testing kit to determine the acidity or alkalinity of the soil before beginning any garden bed preparation. This will help you determine which plants are best suited for your site. Check soil drainage and correct drainage where standing water remains. Clear weeds and debris from planting areas and continue to remove weeds as soon as they come up.

A week to 10 days before planting, add 2 to 4 inches of aged manure or compost and work into the planting site to improve fertility and increase water retention and drainage. If soil composition is weak, a layer of topsoil should be considered as well. No matter if your soil is sand or clay, it can be improved by adding the same thing: organic matter. The more, the better; work deep into the soil. Prepare beds to an 18 inch deep for perennials. This will seem like a tremendous amount of work now, but will greatly pay off later. Besides, this is not something that is easily done later, once plants have been established.

How-to : Pinching and Thinning Perennials

Once you plant a perennial, it does not mean that you will enjoy years of maintenance-free gardening. Perennials need to be cared for just like any other plant. One thing that distinguishes perennials is that they tend to be active growers that have to be thinned out occasionally or they will loose vigor.

As perennials establish, it is important to prune them back and thin them out occasionally. This will prevent them from completely taking over an area to the exclusion of other plants, and also will increase air circulation thereby reducing the incidence of diseases like botrytis and powdery mildew.

Many species also flower abundantly and produce ample seed. As blooms fade it is advisable to deadhead your plant; that is, to remove spent flowers before they form seed. This will prevent your plants from seeding all over the garden and will conserve the considerable energy it takes the plant to produce seed.

As perennials mature, they may form a dense root mass that eventually leads to a less vigorous plant. It is advisable to occasionally thin out a stand of such perennials. By dividing the root system, you can make new plants to plant in another area of the garden or give away. Also root pruning will stimulate new growth and rejuvenate the plant. Most perennials may be successfully divided in either spring or fall. Do a little homework; some perennials do have a preference.

How-to : Planting Perennials

Determine appropriate perennials for your garden by considering sun and shade through the day, exposure, water requirements, climate, soil makeup, seasonal color desired, and position of other garden plants and trees.

The best times to plant are spring and fall, when soil is workable and out of danger of frost. Fall plantings have the advantage that roots can develop and not have to compete with developing top growth as in the spring. Spring is more desirable for perennials that dislike wet conditions or for colder areas, allowing full establishment before first winter. Planting in summer or winter is not advisable for most plants, unless planting a more established sized plant.

To plant container-grown plants: Prepare planting holes with appropriate depth and space between. Water the plant thoroughly and let the excess water drain before carefully removing from the container. Carefully loosen the root ball and place the plant in the hole, working soil around the roots as you fill. If the plant is extremely root bound, separate roots with fingers. A few slits made with a pocket knife are okay, but should be kept to a minimum. Continue filling in soil and water thoroughly, protecting from direct sun until stable.

To plant bare-root plants: Plant as soon as possible after purchase. Prepare suitable planting holes, spread roots and work soil among roots as you fill in. Water well and protect from direct sun until stable.

To plant seedlings: A number of perennials produce self-sown seedlings that can be transplanted. You may also start your own seedling bed for transplanting. Prepare suitable planting holes, spacing appropriately for plant development. Gently lift the seedling and as much surrounding soil as possible with your garden trowel, and replant it immediately, firming soil with fingertips and water well. Shade from direct sun and water regularly until stable.

Problems

Diseases : Rhizactonia Root and Stem Rot

Rhizoctonia is a fungus that is found in most soils and enters the plant through the roots or the stem at soil level. Prevention and Control: First of all, do not overwater and if you suspect Rhizoctonia may be your problem, decrease watering. If a plant is too far gone (all the leaves from the bottom up are wilted), remove it. If your plant is in a container, discard the soil too. Wash the pot with a 1 part bleach to 9 parts water solution. Fungicides can be used, according to label directions. Consult a professional for a legal recommendation of what fungicide to use.

Diseases : Pythium and Phytophtora Root Rot

Rot Rot, Pythium or Phytophthora occurs when soil moisture levels are excessively high and fungal spores present in the soil, come in contact with the susceptible plant. The base of stems discolor and shrink, and leaves further up the stalk wilt and die. Leaves near base are affected first. The roots will turn black and rot or break. This fungi can be introduced by using unsterilized soil mix or contaminated water.

Prevention and Control Remove affected plants and their roots, and discard surrounding soil. Replace with plants that are not susceptible, and only use fresh, sterilized soil mix. Hold back on fertilizing too. Try not to over water plants and make sure that soil is well drained prior to planting. This fungus is not treatable by chemicals.

Rhizoctonia Root and Stem Rot symptoms look similar to Pythium Root Rot, but the Rhizoctonia fungus seems to thrive in well drained soils.

Miscellaneous

Glossary : Border Plant

A border plant is one which looks especially nice when used next to other plants in a border. Borders are different from hedges in that they are not clipped. Borders are loose and billowy, often dotted with deciduous flowering shrubs. For best effect, mass smaller plants in groups of 3, 5, 7, or 9. Larger plants may stand alone, or if room permits, group several layers of plants for a dramatic impact. Borders are nice because they define property lines and can screen out bad views and offer seasonal color. Many gardeners use the border to add year round color and interest to the garden.

Glossary : Container Plant

A plant that is considered to be a good container plant is one that does not have a tap root, but rather a more confined, fibrous root system. Plants that usually thrive in containers are slow- growing or relatively small in size. Plants are more adaptable than people give them credit for. Even large growing plants can be used in containers when they are very young, transplanted to the ground when older. Many woody ornamentals make wonderful container plants as well as annuals, perennials, vegetables, herbs, and bulbs.

Glossary : Annual

An annual is any plant that completes its life cycle in one growing season.

Glossary : Perennial

Perennial: traditionally a non-woody plant that lives for two or more growing seasons.

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