Vanhoutte Spirea

Spiraea × vanhouttei

Introduction to Spiraea x vanhouttei

Vanhoutte spirea is a deciduous, spring flowering shrub. It is also known as a bridal wreath spirea. This shrub has an extremely beautiful display of hundreds of small and mildly fragrant white flowers. It provides for foraging butterflies as well. It grows to be a vase shaped, medium sized shrub that reaches a height of nearly eight feet and a spread of about ten feet. It has alternately arranged blueish-green semi-lobed leaves which are ornamental combined with its form. It is a member of the rose family or Rosaceae. It is a hybrid of Spiraea prunifolia, a parent that shares the same common name. Its other parent is Spiraea trilobata, the three lobed spirea.

When properly cared for, the Vanhoutte spirea can make an amazing addition to any landscape. The shrub should be planted within its USDA hardiness zone range of three to eight. It grows in full sun, but will tolerate some shade. Relative to maintenance, it is often pruned directly after its flowering period. It is recommended that it be inspected for pests and diseases, as it can contract diseases which usually attack other members of the rose family such as leaf spot, fire blight, and powdery mildew (This is uncommon). This plant requires a very small amount of care, however, it can be very valuable as an accent plant or informal hedge.

While reading this web article, you can learn about how to propagate a Vanhoutte spirea, so that it may make a nice addition to your landscape or plant collection.

* Example of kit for cutting production/etc. (W/. heat mats, humidity holding lids, etc.)

Propagation of the Vanhoutte Spirea

Spiraea x vanhouttei can be propagated using several methods, but the most successful method for producing them is by a cutting production. It is a cross between two different species of the same genus. It is preferred that crossbred plants be vegetatively (a method of non-sexual reproduction) propagated to preserve the exact phenotype of the parent plant, as seed is not guaranteed to share the genotype or phenotype of the parent.

Important Notes

* Worker pinches the soil around a cutting -Huws Nursery

It is important to know that this shrub flowers on the previous year’s growth. This is an important aspect to know for cutting propagation methods, because plants prioritize flowering and fruiting for reproduction over survival in stressful growing conditions. One should assure thatflowering/budding plants are not chosen for cutting production because the cuttings will spend their precious storage of energy resources on blooms, rather than adventitious roots. Additionally, it is severely important to inspect the cuttings for pests and/or diseases, as they can cause failure in the propagation process by infecting other cuttings, or even causing a pest/disease infestation where they’re grown, resulting in a total loss of viable specimens. Fireblight is not common but could be an example in vanhoutte spireas. Shrubs that may be suffering by other means such as poor environmental conditions should also be avoided. Drought stress, for example, could lead to less turgid cuttings which could be depleted of water before they can successfully form roots to survive. Keep in mind that nearly any softwood cutting will begin to wilt nearly right after it is harvested, so one must prepare for direct transport to the hormone application and planting process. Temporary cold storage can temporarily extend the time window.

Harvesting the Cuttings

(Diagrams from FloraMax Grow Guides)

Softwood cuttings should be harvested from newer growth, as to not sacrifice the annual bloom on your specimen, as well as improve propagation success. flush of new growth occurring after the bloom. Softwood cuttings (Have not produced bark or hardened off) are preferred for rooting the spirea, which must be harvested at the proper time of year. It is an essential practice to collect the cuttings using sharp and sterilized bypass pruners. (Anvil pruners may crush tissue) Pruners can be sterilized with a 10 percent bleach or 70 percent alcohol solution. Cuttings should be about one quarter of an inch in diameter. The foliage will be snipped off of the proximal end of the stem. The foliage should be left on the distal end of the cutting. Collect a number of cuttings (however many you desire plus an additional group of about 10 percent for error and/or lack of rooting success). A The cuttings should be about four inches with at least four nodes. It is usually recommended to cut extra in the field so that you may make adjustment cuts at your workstation while dipping the cuttings.

Applying Hormones

*Rooting hormone gel (a powder alternative) product example

After collecting cuttings from a selected specimen, your workstation can be assembled. As final cuttings are made for the propagation process. Cuts should be made while leaving 1-2 centimeters on the stem between the proximal end of the stem and the closest node. The proximal end of the stem (which will be placed within the soil) should be cut at a 45 degree angle to ensure maximum exposure to the rooting hormone (for powders). Rooting hormone products contain auxin, a natural plant hormone that, when absorbed by the plant, encourages adventitious root production. The hormone can be applied while allowing the stems to soak in liquid rooting hormone. A 24-hour soak in 0.001-percent auxin rooting hormone (IBA Product such as Liquid Dip N Gro) liquid formulation is one option which would ensure maximum absorption of the hormone. A pre-set concentrate powder such as Hormodin-3 could be applied by dipping the exposed proximal stem end in the powder (Dip cutting in the powder ensuring full coverage of cut surface, and tap excess powder off). Please read the instructions on any rooting hormone product before using it. Generally, the hormone containing product that will be used for dipping should be placed in a secondary approved container for dipping or soaking, as to not contaminate the product container. Be sure that the hormone you are using isn’t more than a few years old, has been in a cool dry place away from sunlight, and hasn’t been contaminated by other plant material. Setting Up an Environment For Growth

(Diagrams from FloraMax Grow Guides)

A planting container(s) should be prepared for your cuttings. It is recommended to be dated and labeled for future reference. Standard or seedling potting soil mix with perlite, vermiculite, and peat moss (pH shouldn’t require adjustment in a pre mixed product). The container(s) should be at least 6” deep and have a heavily perforated base for capillary action of water from the water source. It is recommended to water the cuttings by flooding a tray containing the planting container(s) because overhead watering can cause potassium leaching from the foliage (primary plant nutrient necessary for water handling in plants) or reductions in contact of the rooting hormone within the media. When planting the cuttings, one should poke a hole in the media with a stick and pinching it closed after sticking in a hormone-applied cutting. (Simply shoving the cutting into the soil can cause powders to brush off)

Caring for Your Cuttings

Your cuttings should be properly cared for to ensure successful root production. The air of the environment should be cool and humid (80-100 percent humidity) in order to prevent too much water loss or drying out. The media, however, should be kept warm, preferably by a seedling heating pad (most have a pre-set premium temperature). Lighting should be bright, yet not in direct rays of sunlight. General inspections should be made to ensure that the cuttings survived the initial process, as well as monitoring for root development. Root development can be inspected using a gentle tug with your fingers on the cutting. Dead cuttings must be removed to prevent mold. When plants show strong signs of root development and active foliar growth, they should be up-potted as needed (recommended slow transition between pot sizes for a very fibrous root system development) As well as pot size, the plants themselves should be slowly transitioned between the humid and less temperate environment in which they started in to the outdoors, otherwise they will most likely become shocked, and wilt or die. The entire process can take many weeks for rooting and several months to reach planting size. In time, the Vanhoutte spirea (Below) can reach maturity to become a beautiful, seasonally ornamental shrub just like its parent.

*Adobe Stock - Fair Use Image

Sources of obtained data & information:

• http://www.missouribotanicalgarden.org/PlantFinder/PlantFinderDetails.aspx?kempercode=c293
• https://homeguides.sfgate.com/can-propagate-bridal-wreath-plant-89819.html
• https://psu.instructure.com/courses/1852692/pages/spiraea-x-vanhouttei?module_item_id=23497839
• https://stock.adobe.com/
• http://www.floramax.com/supercharged-cuttings/
• https://www.youtube.com/watch?v=kWkvNEov0ZM