I have a miniature rose that spent the summer in a pot outside in a south facing area – tripled in size and had multiple multi-coloured blooms. It is now in a south facing unheated sunroom that never freezes and sometimes get up to 20 degrees on sunny winter days. How should I care for it over the winter? Can it be planted in the garden next spring? Does it need to be pruned in the spring like a full sized bush? Thanks in advance for your help.
Indoors in a container, your miniature rose needs abundant light, cool airy conditions, high humidity and plenty of water.
Find a location which has maximum light – a sunny windowsill (south or west facing) is ideal. In the short-day winter months extra light may also be needed so, if possible, place the pot near a florescent lamp at night (or use grow lights).
Water liberally, allowing it to dry out between waterings but do not fertilize.
To assist with air humidity (needed by the foliage) a relatively low maintenance approach would be to stand the pot on a pebble tray. This tray should be 2 inches high and can be made of any waterproof material. Place 1 inch of gravel/pebbles in the bottom of the tray, add enough water to come up to just the top of this layer. The stones should be kept wet at all times so top it up as needed as it will evaporate fairly quickly in our dry heated winter air. Stand the plant, in its container on the stones, making sure the bottom is not in the water.
An alternative would be to purchase a spray bottle and using the finest stream, mist the leaves and around the plant several times a day.
When buds start to form in the spring, feed the plant with a liquid fertilizer every seven to ten days if you decide to keep it in the pot.
Or if deciding to put it in your garden – when the danger of the first frost has past and the soil in the garden is workable, your rose can be planted in a sunny location getting at least 6 hours of sunlight daily and you can feed it with a regular garden rose fertilizer, carefully following the package instructions.
Pruning can be done in the spring and this first year, after its move to the new location, I would hesitate to cut it back quite as hard as a regular rose, let it get established first, but you can cut out any branches that are dead, crossing or impact its shape or size. In subsequent years you can prune hard to promote vigorous growth, cutting at a 45 degree angle, 1/4 inch above a leaf axil. Also be sure to remove faded blooms (deadhead) during the season to prolong the flowering season. Always sanitize secateurs for pruning jobs in the garden, especially when going from plant to plant as this will lessen the likelihood of disease spread.
Hope this helps.