From the Board - Samantha Wickham

From the Board

Don’t let the hoggets in with the old ewes.

SAMANTHA WICKHAM

MARLBOROUGH IS a veritable checkerboard of vineyards in different cycles of life, from new developments and complete replanting programmes through to replacing dead or diseased vines.

We travelled the district preharvest to look, from a nursery perspective, at young vines planted last year. It was hard to draw conclusions from such a diversity of vineyards around the region, especially when our sub-regions are so variable. However, the difficulty of growing a young, replacement vine within an existing mature block continues to be a challenge across every aspect of vineyard management.

Stepping back a bit to look at new vineyard developments planted in 2016, it was not an easy growing season. Cold weather and high winds were challenging across all of Marlborough. Broken posts and varied levels of growth were the subject of many conversations. Even the best vineyard managers were concerned about new developments not being as uniform as in previous years, especially in pockets where blocks were more exposed to high winds.

We noticed that growers who used taller (900mm) vine guards had less variation with their new developments. One can only assume this is because the new plants had more protection from the wind. The few weeks preceding the main harvest period assuaged the concerns of many growers, as the plants bolted to catch up once the winds died down and the warm weather appeared.

On par with new developments, blocks that were fully or partially replanted also struggled in this colder, windier season. Coupled with the weather, these vines faced a double bladed sword of also being vulnerable to whatever conditions were left under the ground from the previous vines. In March, we saw replanted blocks that completely surpassed all expectations and thrived, and other blocks where even in the best site conditions we were surprised that the vines managed to survive with so much weed competition, poor soil preparation and lack of management.

The performance of a replanted block is in direct proportion to how much time and attention it is given. Consider how much time you have before you begin a replant, and plan accordingly. Young vine management requires time and attention to detail. If you do not have either, it is best to have a plan B or to rethink a replant. A good plan B could be to take your replanting plan down to a more manageable size, or to hire someone to look after your young vines if you don’t have the time.

Young vines planted to replace dead or diseased vines within a vineyard always struggle. HI-STEM™ tall vines struggle too. There is no golden ticket to fixing this. When an older vine dies or suffers from trunk disease, the root systems of the adjacent vines fill in the space. This is invisible unless you dig beneath the soil. A young, certified, bare rooted vine from any nursery will struggle in these conditions - it simply cannot compete. Often times the dripper is not perfectly aligned with the freshly planted young vine, and the water that the one-year-old vine desperately requires goes towards the overbearing root system of the adjacent neighbour.

Such a poor start in life is also coupled with managers who have little to no time to care for individual young vines planted sporadically throughout a large vineyard. Most

vineyard managers have much bigger ‘fish to fry’, especially with the new spray calendars to which we must adhere. From a nursery perspective, this is always hard to see - we don’t like to witness anyone wasting money or time.

Standing on my soapbox, I think it is time we took a moment to evaluate not only our vines as they reach full maturity, but also our time. Do you have the time and energy to properly replace the dead vines in your vineyard? Perhaps you should ‘fill the gaps’ if your block is looking healthy, there is no evidence of trunk disease, and the vines are less than 15 years old. Keep in mind that a young vine will struggle regardless of whether or not it is a standard height vine or a HISTEM™ tall vine. What you see above the ground at this time of year reflects what is happening below the ground, and often times the root system of any bare rooted vine cannot compete with the mature roots of the adjacent neighbour.

If your block (and I am referring to Sauvignon Blanc in this context as this is the bread and butter of our local industry) is older than 15 to 20 years, and you are even remotely toying with the idea of replanting, perhaps it is best to leave the gaps and save yourself time and money. However, carefully consider that if you do leave the gaps, your vineyard will no longer be commercially viable if the gaps surpass 20% of your vineyard.

If you do replace the individual vines, and if you do choose to consider replanting, say five to 10 years down the track, the situation may occur where you remove the old vines, but feel compelled to leave the five to 10-year-old vines that you used as previous replants. This will lead to a block that is tricky to manage in all areas. It will prevent you from having a ‘clean’ replant, and instead you will have a block that is peppered with older vines that you will have to individually hand harvest so you do not harm the replants. Irrigation will be tricky, as you will not want to keep watering the older vines as they approach harvest, but the new vines will still require irrigation. Retrunking may be a better solution.

To quote one of my favourite customers, “don’t let the hoggets in with the old ewes”. Take the time to consider the age and health/ stage of your vineyard before you choose to replace vines and fill in gaps this winter. There may be too much underground competition to make this a smart solution. If your vineyard is at a point where you are considering replanting, think about how complicated it would be if you had younger, healthier vines peppered throughout a vineyard that you want to replace. Maybe those gaps you leave today will make life easier further down the track.

Samantha Wickham is a director of Ormond Nurseries and a member of the Wine Marlborough Board.